Emulator Cheats

To perform the Mu no Kyouchi, you must have lost a round, and must have the life bar below the meditation bar level (performing meditations raises the meditation bar level). After you perform, you can perform the Issen (BCD). However, Mu no Kyouchi (like Ikari Bakuhatsu), expires after a length of time (the greater the life remaining, the greater the time), after which you can't make use of the power bar again. Mu no Kyouchi can also end if you are hit, so be careful...

When Mu no Kyouchi starts, surprisingly, whatever your life bar value is copied elsewhere, where it starts to drain towards zero. What's surprising is that while the lifebar can go as high as 0x7D, the timer bar (that replaces the power gauge) only goes as high as 0x40 (so any higher it will look like the bar isn't draining for a while).

Anyways, here's a code that will make Mu no Kyouchi last as long as you like - that is, until you get hit.
EDIT: One minor graphical bug is that the timer bar will still be there even if you get hit out of Mu no Kyouchi...

One short followup:

Now, the code for always having the power gauge will allow you to do the Ikari Bakuhatsu as many times as you want (see the topic on Ikari Bakuhatsu on this), but you can still perform the Mu no Kyouchi once.

Not anymore. The following cheat will allow you to, in theory, perform the Mu no Kyouchi many times. (It does not physically put you in Mu no Kyouchi, however). I say theoretically as you may need to have the power bar on all the time for it to be effective (I am not sure as to whether the game checks for this condition)

Also note that with this cheat, Mu no Kyouchi does not end when you get hit. There are also lots of other unexplored side-effects that I won't get too into - I got better cheats to find.

One minor side-effect is that when you start, your character's portrait will show up five or six times for some reason (it will give you the impression that the game infinite-looped) - at least it's less annoying than Chanpuru... Moving your character is a workaround.

To disable Mu no Kyouchi altogether, use the value 0x01.