The Keep on the Borderlands 2025 - Sessions 11 A and B - The Total Party Kill Post

This is a post about choices, for both the party and the DM's side. This will not be a blow-by-blow post like the other sessions. I will have one last session post where the party successfully defends themselves. Let's recap quickly before I get into the mechanics of a TPK and a near-TPK scenario. 

Outside, the orcs, goblins, hobgoblins, and kobolds have arrayed themselves to crush the party. Here are the dynamics of this order of battle. The B2 booklet explains how the two orc bands have an alliance; they are effectively one group. The same goes for the hobs and gobs. 

In every session post, I have stated that every monster group was planning to kill the annoying kobolds until the appearance of the party. The party's presence in the Caves of Chaos has delayed the planned attack on the kobolds. We have three forces outside working together to kill the party. However, they don't entirely like each other. This is important for morale, which is a big deal in BX. 

Here is a link to these books on DriveThruRPG: Basic and Expert. One of the great things about DriveThru is that they actually update titles and send notifications when they do so. Maybe this is really the author doing it. In any case, I noticed that the Expert book has a POD option. As soon as the Basic book has the same, I will order them both. 

Back to morale. 

The orcs will not roll morale if something happens to the hobs and goblins and vice versa. If anything bad happens to the Kobolds, these two groups will react positively, as they want them dead. This will prevent them from running off if the party defeats the kobolds. Also, it allows coloring, as these forces will cheer the party's successes against the kobolds, which is all rather ominous for the party. 

For sanity, I grouped up the monsters: 

• 2 groups of 8 Goblins each 
• 1 group of 10 goblins
• 3 groups of 8 Orcs each
• 1 group of 10 Kobolds
• 2 groups of 9 rats, led by 2 Kobold handlers each
• 2 groups of 6 Hobgoblins 

You see why this ended in both a TPK and a near-TPK. That's 94 monsters and I haven't even mentioned the leaders and their bodyguards. 

Two other events are going on outside. The party's mule has escaped and is running around. It reacts to the monster's movements, so the party does receive an alert when the monsters move. The second event is that the drover family has pulled a wagon up to the southeastern edge of the map with six crossbowmen. They will not enter the fray or the valley, but are watching. 

Inside the cave, we have the party starting in two groups. Belaphon, Thomas the Cleric, and Sybil the second Magic User are all near the cave mouth. There is a raging fire in Room 17. At the end of the last session, Sybil went to Room 17 to see what was happening. 

All of these character links go to PDFs of the character sheets on my Google Drive account. If you like them, you can always use them in your campaign. You could also hit Support Me on KoFi on the upper right to send me money. Either way, I would really appreciate it if you used them at your table. 

At the other side of the map, we have Dorian, Lefty, Punch, Rety, Slammer, and Solvo in Room 18. They are supported by the newcomer party, made up of 2 Magic-Users and one Fighter. The newcomers have already lost a Cleric, a Thief, and a Fighter. The party recovered their bodies in the last session. 

In the TPK scenario, Rety decides to array the party in roughly equal groups to defend both entrances. We have a Cleric, a Fighter, and a Knight at both entrances, plus two Magic Users at each. Solvo the Elf is with the group near Room 18, and Rety is at the other cave mouth leading that group. 

Wave upon wave of monsters eventually breached the caves and crushed the party as they retreated to Room 18. 

The primary issue was that the Magic Users and missile-armed fighters held the monsters off outside the cave entrances using sleep and arrows on whatever wave they were facing. Since the sleeping monsters were outside, they could be woken up again and form another group of attackers. Once the spells ran out, the battle quickly descended into melees that the heroes couldn't win. The archers never ran out of arrows because they were pre-stocked in various places. It simply didn't help. 

In option two, the near-TPK scenario, the party blocked up the secret door and focused on only the cave mouth. Basically, the same thing happened. The party ran out of spells and retreated to Room 18. They managed to unblock the secret door and fled to the waiting wagon. Once the party started the breakout, I ran the scenario 3 times. The Fighters, Clerics, Rety, and Knights died over and over again, and usually only the Magic-Users made it to the wagon. 

What helped the party was that ALL of the monsters participated in the breaching of the cave mouth, leaving a very weak force outside to stop the party. Whoever made it outside simply needed to outrun the leaders and bodyguards, who were already disinclined to get into melee. 

I'd like to talk about this scenario because I tried several game-breaking options to allow the heroes to escape. From the DM's perspective, these were all bad choices because they would have killed follow-up sessions and possibly my whole campaign. In my opinion, TPKs happen because players make bad choices. It is not up to the DM to try to fix it by breaking rules. Let the party find out what works and what doesn't. 

First, I did the easy thing and cheated by letting the magic users enter the fray with undeclared spells. I simply let them have whatever spell they deemed necessary. This is a really bad choice, AND it didn't help the party at all. I posted about letting Magic-Users hot swap spells in Session 6.5. This is a non-combat event, NOT at all appropriate for what happened here. Second, allowing MU's the ability to just select spells at the time of casting gives them too much power and takes away from the spontaneous casting that Clerics can do. This would damage future events by giving too much power to the spellcasters. I do let clerics spontaneously cast. If your god needs you to do it, you can do it. Clerics have that kind of power. Magic-Users do not. 

The second thing I tried was even more egregious. Since the party was facing total extermination, I allowed anyone to fire a crossbow at the onrushing horde of monsters. Lefty and Punch shouldn't use crossbows, but I justified this as they started as crossbowmen. That feels bad, but it has some logic to it. 

Magic-Users firing crossbows is also "just ok", as they would face serious penalties to their die rolls.

Clerics and bows should be right out. They won't use sharp weapons against living creatures by choice or oath. Sharp weapons tend to be ineffective against the undead in most cases. They have better tools in these scenarios, like spells or turn undead.

In all cases, none of this cheating actually helped the party, and as a DM,  I damaged my ability to run future sessions because I broke major rules. I would never do this with players at the table. 

I DO allow MU's and Clerics to use bows and sharp weapons under very strict conditions. Clerics can have the ability to use ANY weapon under non-combat conditions. They can't hurt people with them, so this is limited to sparing or target practice. They never get to roll damage, so no harm, no foul. 

For Magic Users, I allow them to use darts for 1d3 damage at very close range. They can have a very wimpy hand-pulled crossbow for flinging darts if they so choose. Most players try this and determine if hand-throwing a dart and firing one from a crossbow does the same exact thing; they won't carry the crossbow to save weight. The weak, hand-pulled crossbow is a campaign flavor thing with some historical notes. 

Did you know they made clay pellet bows and crossbows for game hunting? Stonebows were completely ineffective in warfare. I would imagine someone tried it to find out how bad it was. Of course, there is a video or 10 on YouTube. 

I also have a rule that Magic-Users can use swords under limited conditions, too. Sybil has a short sword. She is limited to 1d4 points of damage. If a fighter used it, it would go back to its full 1d6. Magic-users are ineffective with swords, but I love the idea of Gandalf and his sword. This seems to be a good compromise, as there is considerable crossover between a small sword and a big dagger. I wouldn't let them pick up and use a 2-handed sword, and no one has ever asked to do so. Of course, this is one of the things you can do with the original rules combat, where everyone did 1d6 per attack, no matter the weapon. 

In these two scenarios, the party's choices and the DM's choices lead to a Total Party Kill and a near TPK, with only random characters escaping over a couple of replayed events. 

In the next post, I will do a nearly round-by-round description of how the party avoided both of these scenarios. The clever party came up with some great ideas that required some game-changing adjudication by the DM. This would completely change the flavor of a campaign and needed to be handled strictly by me so as not to cause problems in the future.  

The Keep on the Borderlands 2025 - Taking Stock

I have finally gotten around to scanning all of the character sheets I am using. I hate my HP scanner, and I am on the lookout for a new printer/scanner combo.  

My default character sheet is the one from OSE/Necrotic Gnome. This is a funny choice for someone who created their own character sheet, but this one is better than mine. At least for B/X games. The one I created was done in 1989 for AD&D 1e with Unearthed Arcana. You can get it at DriveThruRPG at that link. 

Here are the characters in alphabetical order: 

• Belaphon - Magic User
• Dorian - Cleric
• Lefty - Knight
• Punch - Knight
• Rety - Thief
• Slammer - Fighter
• Solvo - Elf
• Sybil - Magic User
• Thomas - Cleric

You can also download a single PDF of all of them here. All of these links lead to my Google Drive. I don't believe they require an account to view and download. 

The individual characters have a lot of resources and gear. 4 of them have Bags of Holding. Rety made sure that everyone with a Bag of Holding had enough food and water inside to support the whole party for a day or so. 

Also, as mentioned in Session 6.5, all of the magic users have shared their spellbooks. This was done at Rety's request to strengthen the party. Solvo, Belaphon, and Sybil have access to the following spells: 

1st-level spells:

• Charm Person
• Detect Magic
• Floating Disk
• Light
• Magic Missile
• Read Magic 
• Read Languages 
• Shield 
• Sleep

2nd-level spells:

• Continual Light
• Invisibility  
• Phantasmal Force
• Wizard Lock

This is a devastating array of magic. 

Rety also made the fighters and clerics pre-stage weapons in locations. In each room the characters control, there is water, food, 40 arrows in two quivers, 6 crossbows and 60 bolts, and 12 spears. Slammer, Solvo, and the two Knights also have shields and polearms prepositioned in the locations they believe they will be most. They don't have enough to supply every room. 

The heroes are now divided into two groups, one at each entrance to their system of caves. This is a problem as they can't communicate and support each other. Also, the fighting men are separated from the spell casters. 

The party does have a pair of minor advantages. First, the escaped mule is causing distractions outside; various factions want to eat it. Second, the drover band is waiting at the base camp for the heroes with six archers. Since they see the smoke, they are on their way to see what is happening. 

I have actually played this scenario out three times, with very mixed results. One was a TPK, one was a near TPK, and the third was a victory for the party. I will have a short post for the two TPKs and why those happened, but I will have an extensive post on the heroes' victory. 

Having the party succeed required careful gameplay by the characters and a ton of adjudicating by the DM. Part of my reasoning for posting these solo sessions was fun, and the other part was to talk about how I make choices as a DM. The last post in this series will show how a DM can fairly referee a session that results in a win for the party without turning monsters into dumb zombies. However, some of these choices can come back to haunt the DM later. 

Let the Fall Begin

A couple of days ago, I cracked the joke that the hours of daylight in Western New York are less than the runtime of the three extended editions of The Lord of the Rings. It feels true. 

This is also the time of year when I struggle to get people to play games with me. I am gearing up for two pre-holiday trips, one personal and one business trip. The Bills are on, hockey is on, and the holidays are rushing at us. I can get people over here, but there are too many distractions to play games. This is the season of friends and family, sports and food.

As of late, I am doing a solo run through of Keep on the Borderlands. I am on session 10, and I don't plan on running past session 12. I would like to complete this in the next week or two and move on to painting figures. You can see that I have the figures I need in session 10. 

Since I want to end the year painting, I would like to play some more Battletech. I also have a game called A Billion Suns that I'd like to play. 

Once the Keep sessions are complete, I want to kick into planning posts for next year. To that end, I'm sharing the last couple of modules and books I've purchased. 

OSR Solo: Since I have been playing solo, this book is instrumental for solo play. I am pretty good at improvising, but this throws some curves into gameplay. 

B2 The Keep on the Borderlands (Basic): Levels 1 to 3. Made for B/X, but I have also played it with AD&D. AD&D causes issues, which I will talk about at the end of this series of posts. Click this link to read the sessions. 

L1 The Secret of Bone Hill (1e): Levels 2 to 4, for AD&D. True fact, when I was in sixth grade, my school had a collection of D&D books in the library, and this was the only module they had. We had a D&D club and played it twice. 

X1 The Isle of Dread (Basic): Levels 3 to 7 for B/X. Assuming anyone survives the Caves of Chaos, this will be my next solo play-through. 

B1-9 In Search of Adventure (Basic): Levels 1 to 3, for B/X. I have never played this set of modules. Maybe I can gather a gang of humans to run through all 9 adventures in 2026. 

S2 White Plume Mountain (1e): Level 5 to 10 for AD&D. I have never successfully completed this module, either as a player or a DM. It's deadly, and I can't believe it's meant for 5+ level characters. It has 3 of the most iconic AD&D weapons in the lore. I want my characters to get those. 

G1-3 Against the Giants (1e): Levels 8 to 12, for AD&D. Again, this is a modole of I have never completed. It is pretty deadly for the party. 

Old-School Essentials Adventure Anthology 1: This is a great series of adventures, ranging from levels 1 to 9. It was written for my new favorite set, OSE. 

Fiend Folio (1e): This one is not a module, but an old AD&D companion book to the Monster Manual. Since I received this book fourth, I never actually obtained Monster Manual II. I might pick up Monster Manual II.  

Do Not Let Us Die In The Dark Night Of This Cold Winter: This is a standalone game that can plug into D&D. I have played through a couple of times and really enjoy it. I would like to see if I can do a play-through with friends again before the end of the year, but it is really the opposite of the holiday season. We'll see if anyone feels like it. 

I also have this cool D&D product I'd like to review. 

I have a few other non-blog projects planned, like a mini-staycation at the beginning of December. I will be doing a cleanup and decluttering of the house and garage. I also need to do some work in the basement. That might come up on Tog Side Channels. 

The Keep on the Borderlands 2025 - Session 10 - Dragon Fire and Prune Juice

Good Evening! I am itching to paint some figures, but I also don't want to let this series go. Please excuse the unpainted and half-painted figures.  

Our party was surprised by a well-armed band of adventurers wandering the valley of the Caves of Chaos. They were more surprised that their mule had escaped the kobolds for several days running and had become a regular denizen of the Caves. 

Norin spotted the new group first and alerted everyone. The two Knights blocked up the secret entrance to the ogre cave with the stone treads and met the rest of the party at the main entrance. Rety and Celia wormed their way under the chain and wheel contraption for a better look. 

Rety, I think.

"The first one is a Thief," whispers Rety. "They have two Fighters and two Magic-Users." 

"Right," answered Celia. "And the skinny lady has to be a Cleric. Look at that holy water sprinkler."

Rety hissed in amusement. The "sprinkler" was studded with large metal knobs, and the woman appeared like she watered it with blood, frequently. 

Celia crawled back to explain the situation before Rety made a decision to call to the newcomers. They looked mean. She never got the chance. 

The other party turned away, looking to the kobold caves. 12 of the little beasties came out in formation. 6 held large shields with large spikes on the bottom. In their tiny hands, they looked like mantlets, a piece of siege equipment the Castlian brought to the Keep. The other six lugged crossbows, two each. They only ventured 20 feet out of their cave, and the shield bearers drove the spike of each shield into the ground. 

One of the women, a Magic-User, waved her arms, and an eye-bending shimmer of light appeared between the groups. Three bolts shattered against the shield spell, but a fourth winged the Cleric who was too wide of the barrier. 

As the newcomers took refuge behind their shield spell, Rety dragged her belly on the floor to get back to her team. 

He looks like a Punch. 

"Punch and Lefty, open the secret door! Slammer and Solvo, get your bows ready, but wait for my signal. Dorian, back them up, but don't expose yourself. Bel, give them a shield," she ordered. The men ran off to comply. 

"Thomas, I want you here with Dorin and Celia. I want you to lift the chains and wheels when I call." 

They nodded and took up the rope Dorin had rigged to his contraption.  

"Come on, Sybil. On your belly, with me," said Rety.

Sybil took a crossbow, a quiver of arrows, and another of bolts with her as she slid on her back. She was ever non-compliant. Rety kissed her magic ring of protection and wiggled her way back to the entrance. 

The newcomers and the kobolds hunkered down behind their respective shields, exchanging missiles. It was clear the newcomers were considering the caves to the south with trepidation. The kobold crossbowmen were working with their shieldbearers. The bearers reloaded for them, allowing them to fire every round instead of every other round. 

I deemed this effective but slow. The kobolds always lose initiative when doing this and also fire last. I also deemed the prior two sentences should have been one sentence with a semicolon connector, but no one but AI uses semicolons in 2025. Goddamn AI, bane of my existence. This is why I use a 1999 iBook for writing. 

It gave me a semicolon like I wanted. However, it left the redundant "but". 

I thought Bel would be younger.

The one thing that AI does do well is track characters and locations, so long as those locations are well labeled. Bel, Dorian, Lefty, Punch, Solvo, and Slammer were in room 22, removing the stone treads they had just put there. Punch and Lefty, trying to be true Knights, didn't swear too much. Rety and Sybil were in the cave mouth while Dorin, Celia, and Thomas were holding the rope to let them back in quickly. The 3 mules were munching breakfast quietly in the L-shaped hall, left of the intersection to the cave mouth. 

And in room 17, 3 giant rats wiggled their way out of the debris blocking the stairs. They snuck up on and surprised Dorin, Celia, and Thomas. Instead of attacking, all three went through the motions of washing their faces with their paws. A small necklace fell from each rat's neck before they fled back to room 17, with Thomas in pursuit. Dorin inspected the necklaces; each was a simple piece of twine with copper coins strung on it. 

A very militant-looking Cleric. 

Thomas entered room 17 in time to see the rats disappear back into the pile of debris clogging the stairs. He couldn't stop them. He also couldn't think of a single reason why they would enter and then flee. Cursing, he retreated back to the cave mouth. 

"I'll do the missiles, you do the shield," Rety said to Sybil. 

Sybil nodded. All of the action was happening to the left of the cave mouth. Rety moved to the right to get a better angle and waited for the fighters to appear from the ogre cave. 

In the meantime, the new Fighters unleashed arrows on the kobolds, and the Cleric and the Thief pelted them with bullets. It was a stalemate. The kobolds wore chain armor and had a plus 2 bonus from the giant shields they hid behind. Relatively speaking, they had a wall rather than individual shields. 

Rety edged to the right of the cave mouth, trading range for a better angle. When the fighting men stepped out, she struck one kobold dead with an arrow. The fighting men knew a signal when they saw one. Punch and Lefty charged, Solvo and Slammer arching arrows over their heads. 

And the trap was sprung. 

From above, 6 bolts whistled overhead, striking both of the new Fighters and one of the Magic-Users. Mercifully, it wasn't the Magic-User controlling the shield spell. 

At my table, once a spell is in effect, except if the description says otherwise, it will not fall. Unless the caster died, that is. If a caster is getting ready to prep a spell and gets hit, I declare the action is prevented. They don't lose it; they just can't cast it now and have to start over in the next round. If they have completely prepped the spell, then get hit, that hit foils the spell and results in losing it. I am semi-generous because of the relatively few spells low-level casters have. In AD&D, this is a common thing. Due to the way B/X works, it is far less common.      

The newcomers are under serious threat, but not completely screwed, yet.

Slammer. The name was taken from the book
What is Dungeons and Dragons?

In the next round, Solvo, Slammer, and Dorian fired at the hobgoblins to break up their reloading, while Lefty and Punch advanced on the Kobolds. Slammer rolls a luck 20 and 6 combo, killing one hobgoblin. The other Magic-User and Sybil threw up shield spells. Bel hung back since the team was doing well. 

The hobgoblins retreated back out of sight to finish their reload. Rety downs another kobold with a good roll. The kobolds fire furiously, 11 shots that all miss because the heroes have bunched together behind the shield spell. 

There is a difference between crossbows and arrows, one part training and one part mechanics. Arrows obviously can arch through the air to hit targets at greater ranges. Crossbows can also arch, but they lose effectiveness fast. It's harder to do and not obvious to do unless one is also an archer. The hobgoblins aren't great crossbowmen or archers. 

Elves, like Solvo, look better without helms. 

Solvo and Slammer loosed two arrows over the ridge where the hobgoblins are hiding. They missed, but the arrows gave the hobgoblins pause, and they took cover. Rety and Dorian took potshots at the kobolds. In the momentary break, the newcomers begin to move to the orge's door and safety. 

The heroes won the initiative and began moving, while Rety's team discouraged the enemy with additional missile fire. The problem with winning initiative is that you go first. There were no easy targets, and all of the party's missiles were wasted before the hobgoblins popped out to respond. 5 of the kobolds do the same. The effect was devastating. The only newcomers not hit were the mages behind their shield spells. Punch slung his shield to pick up the Thief while Lefty assisted the Cleric in a hobbled run to the orge cave. 

The party lost initiative, but only had to fend off the kobolds for the round as the hobgoblins reloaded. Rety struck another kobold, causing it to leap behind a shield. 

Back inside, Celia noticed an odd noise, a gurgling sound. She checked the water barrel and shrugged. Thomas sends her to check the other barrels in 17 and 18. Celia dashed to room 17 first, as room 18 had ready guards. 

Celia discovered the water barrel in room 17 was also intact, but an odd smell permeated the room, like oil, alcohol, and strangely, prunes. Outside, above the mouth of Rety's cave, a mixed group of goblinoids rained bolts down on the newcomers and the Knights. Rety was grazed by a spear from above, and Sybil found herself hemmed in the entrance, her shield spell protecting only her. 

"Lift!" yelled Sybil. 

The two heroes pulled the chain and wheels out of the way. The escaping party, the Cleric, Thief, Fighter, and Knights, bore the brunt of the missile fire. The Thief was killed instantly, and Lefty threw the unconscious Cleric over his shoulder. 

Celia searched around the room for the source of the smell and gurgling. It came from the clogged stairway. A fluid ran down the slope from under the debris. The smell of prune brandy*, oil, and other vile and volatile liquids accompanied it. A blue flame licked over the surface.

"DRAGON FIRE!" yelled Celia. 

A massive whomp shook the Caves of Chaos, stunning everyone near room 17. 

Sybil.

Lefty and Punch deposited their charges in the orge cave and took up a rear guard as the other retreated with the dead and wounded. Thomas flailed, clutching his ears as smoke wafted from room 17. Dorin lay still. 

Rety and Sybil emerged from under the wildly swaying chain of wheels. Sybil ran off, following the smoke, while Rety collided with Bel coming from the other direction, seeking answers or at least orders. Rety motioned for him to tend the wound and dashed to the western rooms to see what other trouble she could find. 

Bel tended to Thomas, knowing the Cleric could help Dorin. Rety continued on to the room with the secret door.  

The scorecard looks very bad. Rety, Thomas, Punch, Lefty, the two Magic-Users, and the new Fighter were all wounded. The new Cleric, a Fighter, and the Thief were dead. So were two of the three mules. Celia was missing, and Dorin lay dying. The new Magic-Users only have one 1st-level spell left each. Bel, Thomas, and Dorian have all of their spells available, while Sybil has expended one first-level spell.  

Lefty matches Punch.

Outside, the orcs came down from their perch as the kobolds, goblins, rats, and hobgoblins advanced on the main entrance to the heroes' home. Rety* and the Knights argued about blocking up the secret door. 

(*Edit - I botched reading my notes and said this was Sybil. Sybil went the other direction and is nowhere near the Knights. It was Rety.) 

Under all of the shouting, Punch muttered, "If I live through this, I'll start using my real name." 

Lefty and Rety looked askance at him before continuing their bickering about honor vs. hiding.  

In Session 11, we will learn what the Caves of Chaos have in store for the heroes and how they will react to this loss.  

*Prune brandy is just the sort of stuff that I would think goblins would drink. In the real world, as near as I can tell, no one makes actual prune brandy. Plum brandy is unaged brandy, while what is called prune brandy is aged plum brandy. That is aging in barrels, not aging the plums or prunes. I would think there would be a difference. 

I am throwing an ad here for very little reason. I strongly suggest reading "What is Dungeons and Dragons" by John Butterfield, Philip Parker, and David Honigmann. I have seen several covers, but I don't know if they were different runs or different covers for different markets. As always, as an Amazon Associate, I earn from qualifying purchases. The first link leads to my 2020 review (below the picture), and this link leads to an Amazon page for the book. 

As always, thank you for reading along and supporting me. 

Why Descending AC?

Descending Armor Class is a trope of BX, but as new retro clones appear, you also see THAC0 and Ascending Armor classes. Those are all choices, but which is best depends on who and when you are. And to be honest, which one you pick makes no difference. 

Way...way... way... back... to the DMG for AD&D, AC had a different mechanic than simply beating a number. There was a chart or series of charts that had endpoints. Characters reached a certain level where it was simply listed as "level n+". For Fighters, at the first level, you needed a 25 to hit AC -10 and an 11 to hit AC 10. Going to the other end, it didn't matter how high your level was; there was just one line labeled "This level or over". There were bounds to the charts. 

But if you ignore boundaries, all three attack systems are basically the same. 

For descending AC, you could fill out the Attack Value Matrix on your character sheet like so: 

Except this tool was in the hands of the DM! You would tell your DM what you rolled, and what your bonuses were. 

It would be up to the DM to consult the chart and tell you if you hit. What number you really need to succeed is obscured. This makes B/X and AD&D e1 especially deadly because you don't know what you don't know. Also, the tables had steps or jumps in probability not so much to keep one guessing, but due to the boundaries set by the charts and the progression of classes.   

For THAC0, instead of using the chart, you'd figure out what you need to hit AC 0, then calculate what you need to hit. In this case, roll a d20, subtract your opponent's AC, and see if it was better than what you needed. The two issues with this method are: first, the probabilities are different, and second, the monster's AC isn't obscured at all. 

You could either calculate on the fly all the time or fill out the Attack Value Matrix. It didn't matter, except as before, the tables were often not listed on your character sheet, and it still felt like the DM was slightly obscuring the needed info to calculate a hit. 

For Accending AC, you roll a d20, add your bonuses, and compare that number to your opponent's AC. This is different because this is all on the players, not the DM. A chart isn't necessary at all. 

So, why was Descending Armor Class ever a thing? 

A lot of people would answer: "Wargames have charts, and that is simply the way it was done". That's true, not the whole story. 

It comes down to how you were taught math and WHEN. For people coming of age in the 1960, you'd have a very different way of learning math. Check out this video. 

Believe it or not, the audio of this video is from 1965 as an objection to what was called "New Math". New math was what was taught from 1965 on. Math teaching changes. If you played D&D in the 1970s, you have experienced 4 changes in how math was taught. 

So, when Gary Gygax learned math, he didn't learn like the youngsters today. But he knew what he was talking about. 

Ask yourself, what is 3+4? Virtually every adult has this fact memorized, and no real math occurs. Even if you use your fingers. 

We'll call this the 7 configuration. 

Or does it? 

Ask a young child the same thing. 

Literally, 3 and 4. 

They will probably hold up 4 fingers on one hand and 3 on the other. There will be a pause while they put down one figure from the 3 hand and put up another finger on the group of 4 hand. 

And we are back to the 7 configuration.

Ok. They did some math right there, but what exactly did they do? Can you show your work, like the video jokes about? 

Yes, but you need to think in terms of spaces, not numbers or fingers. Theoretically, everyone has 10 fingers. 

 

Most of the time, I have 10 fingers.

OR we have 10 places to record things... numbers usually. But it could be pips, or apples, or oranges. 

Ok. So what is the point? 

We are back to the young child. The young child did some sleight of hand. First, he or she held up 4 fingers, then 3 fingers, then showed you all of them together. Next, he moved one figure from one hand to the other, to land in the seven configuration. If you live in a different country, which fingers you show would probably be culturally different, but still showing 7 fingers between two hands.

Now, let's show the work: 

10+4=14
10-3=7
14-7=7

Did I just do addition with subtraction?

Yup. 

That Trad Math, if you will. To add and subtract, you have a boundary - 10 fingers to hold information. If your range is between -10 to 10, you never need more than 10 fingers. 

Let's take slightly large numbers to prove it works, with more than 10 slots. Consider 47+38. 

100+47=147
100-38=62
147-62=85

Notice that for bigger numbers, I need the place above it. In this case, for numbers between 1-99, I need the 100's place. 

That is very different from putting 47 on top of 38 on the page, adding 8+7 for 15, adding 4+3 for seven, shifting the 7 to the left to represent the 10s place, and adding 70+15 to get 85. Watch that video again. Tom Lehrer found New Math totally perplexing. And it IS to some people. 

We are missing a step. In 1989, there were the NCTM Standards, which were different standards than New Math and also very different from the Common Core. The order is Traditional Math, New Math, NCTM Standards, and Common Core. All of which you would have lived with if you played D&D in the 1970s. 

This is why there was a progression from Descending Armor Class, to THAC0 and finally Ascending Armor Class. AD&D and BX are in the transition period between Traditional Math and New Math. 1989 marks the transition between New Math and the NCTM Standards. And Third Edition D&D and above marks the transition between the NCTM Standard and Common Core. 

Funny how that all works, with the dates lining up so neatly. 

So at my table, Traditional Math is king, with Descending AC. At your table, I bet it's something else, and you will have to thank your math teachers for making you just as right as me.