I've been thinking about the Playstation game Bushido Blade (here's a video). It's a fighting game without health bars. A character dies instantly if struck in the head or torso.

The one-hit kills place a premium on evading and blocking attacks. This makes sense from both a realism and a cinematic perspective. e.g. Batman typically has to do backflips or something to avoid gunfire.

Bushido Blade, as an action game, leaves the evading and blocking to the player. I'm left wondering one thing: how would I possibly adapt this for a turn based game?

In every turn based game I've seen evading attacks are represented by a random chance for an attack to do no damage; a "to-hit" rating. If I combine that with Bushido Blade style one-hit kills then a character's life is entirely in the hands of the Random Number Gods ("The only people who should roll dice are those who are prepared to roll a 1.").

Are there any non-random ways to represent evasion in a turn based game?

There's a few games, like Gladius and Costume Quest, where minigames and QTEs come into play. There, they modify your damage or evasion chances, but you could probably come up with a decent system based around it.

For example, the attacker could perform a precision-timed event to determine where their attack lands, or how powerful it is. The defender might be guided along an evasion sequence, and the resulting damage could be based on the difference between their results.

I'm left wondering one thing: how would I possibly adapt this for a turn based game?

In every turn based game I've seen evading attacks are represented by a random chance for an attack to do no damage; a "to-hit" rating. If I combine that with Bushido Blade style one-hit kills then a character's life is entirely in the hands of the Random Number Gods ("The only people who should roll dice are those who are prepared to roll a 1.").

Are there any non-random ways to represent evasion in a turn based game?

Quest 64 was turned based. During your turn, you can move freely around a small circle of movement area, within a much larger circle of the battle area. When it was the enemy's turn, he uses a move that physically shoots out some kind of magic, and you regain your movement for a split second to physically dodge the magic.

There was also a tiny percent chance of randomly missing ("Miss!"), but that percent would get alot higher if you were farther from the physical magic attack, and wouldn't even bother saying "Miss!" if you clearly weren't touched by the magic.

Here's the first boss battle in the game: [youtube]

You'll notice on the few misses of the player, his attack was aimed slightly short or to the side, and so had a greater chance of randomly Miss!-ing. You'll also notice that the boss's attacks are so far off (because of the player dodging) that it doesn't even bother saying "Miss!".

Enemy attacks sometimes have shapes to them - in the video above, the boss mostly just shoots beams of fire-magic. You can either dodge to one side or the other, or you can perfectly align yourself inside the tunnel-like beam, and it'll pass around you - pretty difficult to do. If you get too close to the boss, he'll switch to another attack where he causes earth spikes to shoot up from the ground all around him in an AoE. If you're careful, you can run closer and be protected in a tiny area around the boss himself, where the boss doesn't get hurt and where you can also not get hurt.

This particular boss is rather easy to dodge, but that doesn't apply to the entire game. Some enemies do things like cause avalanches of rocks to fall down, and you have to dodge them all, or else shoot semi-homing arrow missiles at you, or have other methods of attack.

The easiest thing is to keep your distance and blast away with magic, but that's not always an option, and even then you can still get worn down by enemies as they get hits in here or there, and as you run low in mana and don't want to waste items. Melee attacking requires you to get real close, but each melee attack gets you some mana back.

Here's the second boss battle, after several more dungeons - maybe an hour or two gameplay later: [second boss]

At the end of each turn, where you end up is the center of the new circle of movement you have.

You can get magic or use an item that temporarily increases the radius of your circle of movement.

If you, over several turns, move to the edge of the entire battle area, you can escape battles (except for boss fights) if you intentionally go outside of it and press the 'Action' button.

You can add a delay to every action (or at least to slower actions), giving you a natural opportunity to evade it (provided you have enough time).

Say you are going to act next in 5 ticks of game time, and your opponent begins an attack that takes 6 ticks to land. Your turn will come up before the attack connects, letting you either move out of the way of the attack or perform a guarding action. Hitting someone is then a matter of either timing your attack right so they don't have time to evade it, or positioning yourself such that they cannot physically move to evade it.

Then like a fighting game, you can have different amounts of hit/block stun on moves, or punish someone for missing an attack provided you can move and attack while they are recovering from missing their attack.

This would work best in a team based game, otherwise it would be too easy to just pick the optimal move at all times and avoid everything. You'd also want area of effect and other such wide angle attacks to limit evasion and be able to be used to position your opponent where you want them. Same with attacks that push your opponent around, being able to shove a blocking opponent into the path of another of your character's attacks would make for an interesting mechanic.

So here's how I see the problem:

A) You have your turn, you spend it to do one or limited amount of actions

B) You must evade the next attack or you die

=> C) No other choice but to choose evasion as an action or one of them on every turn

So you seem to need some form of evading that isn't just an action you choose on your turn. I don't think some quicktime event like requiring a keypress each turn would be too fun or meaningful gameplay either.

How about working with chains of actions that must be proper in order not to die against the current opponent? You could attack, but you must only perform certain kinds of patterns in order to keep your defense and evasion abilities intact enough? Maybe eventually you could "stagger" the enemy so you don't need to worry about defense so much and can land the big damage moves? Would be a bit like FFXIII reverted back to turn-based combat and with defense and forethinking playing much more significant part.

Are there any non-random ways to represent evasion in a turn based game?

Like jbadams suggested, double-blind choice. Both players/AIs make their decision simultaneously before seeing what the opponent decided. This promotes predicting and "reading" the opponent, and tends to make the game massively deeper than it is with visible information.

David Sirlin's "Yomi" card game is all about that. You can try it at fantasystrike.com. His earlier, simpler game "Kongai" at Kongregate is also based on the same thing; Kongai is dead as a multiplayer game but you could check it out for inspiration.

Another possibility is that after the opponent launches an attack, the player gets a chance to react to it with different defensive moves like block and evade. These would of course need some kinds of tradeoffs; maybe evading puts you to a state where you can't immediately evade again and any attacks you make are weaker ("off balance") while blocking eats into a limited supply of stamina/energy.

Or a combination of the two with limited double-blind. You could see the opponent is launching an attack, and get to pick a response afterwards, but you won't know if the attack is real or a feint before you do. Then, "do nothing" or "attack" might also be valid defensive options because they are good against a feint.

How about every turn each player issues both offensive and defensive actions. An offensive action is an attack, and a defensive action guarantees you immunity from some specific attack or set of attacks for X turns? High level characters have a variety of offensive actions they can take, and thus have a higher probability of bypassing the defenders defensive actions.

I remember playing Super Mario RPG. In it when you are attacked you could reduce damage or even evade attacks all together depending on your ability to press specific buttons during enemy attacks.