[Radek]

To become a Zenmaster, you have to collect four "tomes of wisdom", four books (Tome of Fire, Earth, and so on), which you find during your travel through Gael Serran. Once you have collected all four tomes, give them to your future zenmaster, make sure that the future zenmaster is the active character (the one that can speak, buy, sell, etc.), enter any Bushi Dojo Guild, and wait. The candidate will be promoted to a Zenmaster.
The career of the future zenmaster does not matter. Even a character with a base role (thief, warrior, etc.) can become a zenmaster. Also, the future zenmaster need not be a member of Bushi Dojo. The four tomes in the inventory is the only thing that matters.
Only one character in your party can become a zenmaster (if you don't save the tomes by passing them to another character [img]graemlins/hehe.gif[/img] - see the tips and tricks thread). That's because there is only one copy of each tome in the game. Naturally, you can become a zenmaster, reset adventures, and play the game again with your new zenmaster. New four tomes of wisdom will appear in the game after resetting adventures and another character can become a zemnaster. And so on.
One last thing: the last tome of wisdom is in the Pyramid. Therefore, don't be too unpatient when searching for the tomes.