Yojimbo's stats matter not in deciding what attack he uses. And you're semi-correct about his overdrive, but only for the Intl/PAL versions of the game. When Yojimbo has a full overdrive bar in the NA version, it adds two points to a formula called motivation. In the Intl/PAL versions of the game, it adds twenty, making it much easier to have him perform Zanmato. You also increase or decrease your chances of seeing Zanmato depending what happens to Yojimbo and what attacks he uses. For instance, everytime you pay Yojimbo zero Gil, he'll automatically Dismiss himself, and your compatibility will go down by 20. The compatibility is an extremely large factor in deciding what attack he'll use. The max compatibility you can have with Yojimbo is 255. However, depending on Yojimbo's attack, his compatibility will go up. For instance, if he performs a Wakizashi against one enemy, his compatibility will go up by one. If he uses Wakizashi against all enemies, his compatibility will go up by three. And if he uses Zanmato, it will go up by four. Now, for his attack to execute, it goes through an extremely large formula. First off, it takes your compatibility, than, depending what version you have, will divide it by either five, or 1024. Than, it adds another motivation set and that's figured out by how much you paid Yojimbo. If you paid him 100,000 in the NA version, his motivation will rise by 30. (If paid 100,000 in the Intl/PAL versions, his motivation will raise by 72.) Than, the game selects a random integer (0-63) and adds that to his motivation. Than, if factors in the enemies Resistance Level to Zanmato, and finally, it factors in the Overdrive Gauge. If Yojimbo has a full Overdrive, it will raise his motivation by two points (twenty points in the Intl/PAL versions). If the total motivation after all those calculations is 80 or above, Yojimbo will perform a Zanmato. And if you have to pay him 200,000, than you really need to increase your compatibility. I get free Zanmatos at the start of almost every battle. BTW, you missed Luck and Accuracy.
MY Yojimbo's stats:
HP: 14,501
MP: 0
Strength: 255
Defense: 255
Magic: 166
Magic Defense: 143
Accuracy: 255
Evasion: 255
Luck: 26
And might I remind you that Luck is directly related to Yuna's.
