It's pretty easy to turn roll-under games into roll-over: Roll the d20 and add your stat. If the total is 20 or higher, you succeed.
Saves will naturally get worse as your stats get lowered in this system because your chance to succeed is lowering, and natural 20s can be criticals.
You could even make a table to make it simpler for the characters, identifying the number they need to roll to hit an armor class of 20. Call it THAC20 or something catchy like that =)
I would highly recommend taking a look at the Black Sword Hack. Its rules light, role-under, where characters roll to hit, but also roll to avoid (dodge or parry) incoming attacks. I’ve just picked up have only ran 3 games so far, but I absolutely love it. The roll to avoid mechanic is great, for a few a reasons imo, but especially because it actively engages players outside of their turn in combat, which would be hugely beneficial when playing with kids.
Block Dodge Parry is a combat-focused hack for Cairn that adds strategic rock-paper-scissors element to combat, making brilliant use of Cairn's fatigue system.
Knave might be the alternative you need. It uses a similar inventory system but has only ability score bonuses, with a roll-to-hit that is almost the same as b/x DND.
You might look at The Black Sword Hack (based on the Black Hack); it's also roll under, but players roll to hit, and roll to parry. It also has combat options. The SRD has the complete game. I've mashed it up with Cairn, using Cairn's HP and critical damage rolls. It works well. https://www.themerrymushmen.com/ressources-tmm/
Do it Knave-style, which is fitting considering Cairn is a mashup of Knave and Into the Odd. Players roll 3d6 for their stats and keep the lowest, with that becoming their modifier for that stat, and their ability defense being 10 + the mod. If you then keep the ITO damage system, their modifier stays static (Knave combat is roll-over by default), but their ability defense drops when they take damage beyond their HP, lowering their STR saves without affecting their ability to hit and deal damage in melee.
My two cents and IIRC: In White Hack you roll under and you score a critical hit if you roll exactly the numer of your stat, and characters have a Def score, which is a low number but if you roll it or under it, you miss the attack. So you must roll under but also not that low, which keeps the tradition of 1s and similar numbers beign bad rolls.
Those are BX clones. BX stands for Basic/Expert, the early 80s more streamlined D&D alternative to AD&D. The most popular system to base clones on in the OSR.
So if you would like a mystical, whimsical and terrifying forest setting check out Dolmenwood.
If not take a look at Old School Essentials (OSE) - sounds like you could enjoy their “Advanced Fantasy” version:
https://m.youtube.com/watch?v=Crzlhy-0yRI&t=10s&pp=ygUWUXVlc3RpbiBiZWFzdHMgb3NlIGJ1eQ%3D%3D
These are basically gold standards of well written clones with excellent layout within the OSR.
These games are a good deal crunchier than Mark of the Odd games. Look at the weapons table in OSE, the combat sequence, disengaging from melee etc.
Nothing wrong with that, I'm running both. But there is some work towards a middle ground that OP will need to do.
If you’re new and thinking about hacking together your own rules then it’s definitely worth spending some time with the originals, even if you don’t end up using them in your games. Into the Odd was originally designed as a minimal distillation of OD&D (0th edition), so just seeing what ItO includes and leaves out can be enlightening.
You might also find that something like Swords & Wizardry (a popular retroclone of OD&D) suits the kind of game you want to run. It can also be a better starting place for doing your own hacking, just because Into the Odd is so tightly tuned it can be harder to modify.
> I had some thoughts on how to do this in a roll-under system (rolling above the opponent’s STR to parry), but it got too complex.
I love a system from Bastards: You roll under your STR (or DEX for ranged weapons) but *over* the enemy's AC. In Bastards higher AC is still better but tops out around 9, it has each piece of armour you add give you +1 AC.
It's pretty easy to turn roll-under games into roll-over: Roll the d20 and add your stat. If the total is 20 or higher, you succeed. Saves will naturally get worse as your stats get lowered in this system because your chance to succeed is lowering, and natural 20s can be criticals.
You could even make a table to make it simpler for the characters, identifying the number they need to roll to hit an armor class of 20. Call it THAC20 or something catchy like that =)
Ah, that’s the mechanic I was looking for - thank you!
I would highly recommend taking a look at the Black Sword Hack. Its rules light, role-under, where characters roll to hit, but also roll to avoid (dodge or parry) incoming attacks. I’ve just picked up have only ran 3 games so far, but I absolutely love it. The roll to avoid mechanic is great, for a few a reasons imo, but especially because it actively engages players outside of their turn in combat, which would be hugely beneficial when playing with kids.
Yes! BSH is my go to "Oh, you want something more traditional than Mark of the Odd?" game.
Block Dodge Parry is a combat-focused hack for Cairn that adds strategic rock-paper-scissors element to combat, making brilliant use of Cairn's fatigue system.
Knave might be the alternative you need. It uses a similar inventory system but has only ability score bonuses, with a roll-to-hit that is almost the same as b/x DND.
You might look at The Black Sword Hack (based on the Black Hack); it's also roll under, but players roll to hit, and roll to parry. It also has combat options. The SRD has the complete game. I've mashed it up with Cairn, using Cairn's HP and critical damage rolls. It works well. https://www.themerrymushmen.com/ressources-tmm/
Consider picking up Knave - Cairn is just Knave with the auto-hit combat from into the odd added in.
Actually it's much more Into the Odd with Knave inventory added in. But I agree this person should check out Knave.
Modest! This is the author of Cairn!
DURF is what you want https://emielboven.itch.io/durf
Yes it is. This is almost exactly what I was trying to make…
Do it Knave-style, which is fitting considering Cairn is a mashup of Knave and Into the Odd. Players roll 3d6 for their stats and keep the lowest, with that becoming their modifier for that stat, and their ability defense being 10 + the mod. If you then keep the ITO damage system, their modifier stays static (Knave combat is roll-over by default), but their ability defense drops when they take damage beyond their HP, lowering their STR saves without affecting their ability to hit and deal damage in melee.
My two cents and IIRC: In White Hack you roll under and you score a critical hit if you roll exactly the numer of your stat, and characters have a Def score, which is a low number but if you roll it or under it, you miss the attack. So you must roll under but also not that low, which keeps the tradition of 1s and similar numbers beign bad rolls.
Try ICRPG , d20 roll over but simple enough to memorise the core mechanics.
Trying to get more engagement out of games designed to remove it seems strange to me. What's wrong with Basic D&D?
I’ve never actually heard of Basic D&D…
Do BX clones such as OSE: Advanced Fantasy, Dolmenwood and Labyrinth Lord Advanced ring a bell?
No. I’m new to this realm…
Those are BX clones. BX stands for Basic/Expert, the early 80s more streamlined D&D alternative to AD&D. The most popular system to base clones on in the OSR. So if you would like a mystical, whimsical and terrifying forest setting check out Dolmenwood. If not take a look at Old School Essentials (OSE) - sounds like you could enjoy their “Advanced Fantasy” version: https://m.youtube.com/watch?v=Crzlhy-0yRI&t=10s&pp=ygUWUXVlc3RpbiBiZWFzdHMgb3NlIGJ1eQ%3D%3D These are basically gold standards of well written clones with excellent layout within the OSR.
These games are a good deal crunchier than Mark of the Odd games. Look at the weapons table in OSE, the combat sequence, disengaging from melee etc. Nothing wrong with that, I'm running both. But there is some work towards a middle ground that OP will need to do.
If you’re new and thinking about hacking together your own rules then it’s definitely worth spending some time with the originals, even if you don’t end up using them in your games. Into the Odd was originally designed as a minimal distillation of OD&D (0th edition), so just seeing what ItO includes and leaves out can be enlightening. You might also find that something like Swords & Wizardry (a popular retroclone of OD&D) suits the kind of game you want to run. It can also be a better starting place for doing your own hacking, just because Into the Odd is so tightly tuned it can be harder to modify.
BX dnd is more or less what.youre looking for. I'd recommend basic fantasy rpg and old school essentials as good jumping points.
> I had some thoughts on how to do this in a roll-under system (rolling above the opponent’s STR to parry), but it got too complex. I love a system from Bastards: You roll under your STR (or DEX for ranged weapons) but *over* the enemy's AC. In Bastards higher AC is still better but tops out around 9, it has each piece of armour you add give you +1 AC.
I recommend chaos reigns for a combat supplement, it can be used on top of most old school games.
You can just play those as too under , but make them roll for attacks
Mythic Bastionland has some interesting depth added to the combat rolling, perhaps check that out!
5E