Welcome to the dojo.
I'm seeing a lot of Jutsu lately. From traditional Japanese "Samurai Jujutsu" to Brazilian Jiu-Jitsu (to the often gaudy websites of those claiming lineage in "authentic ninjutsu"), jutsu is suddenly everywhere.
I guess for me, it started in my early teens, with the ninja fad of the 1980s. Everyone who was anyone in the martial arts was suddenly all about the ninja and their shadowy art, ninjutsu. But sometimes it was spelled ninjitsu, sometimes ninjutsu, and sometimes hyphenated (nin-jitsu). It was all very confusing for a guy like me, whose spelling skills were only passable in English - and who, at the time, had little opportunity for real research into such matters.
So what's the difference? What's the correct spelling? Well, like any other American martial artist in the past 20 years, I've seen and heard every possible angle. Once - and this was recently, mind you - I got an interesting explanation from a so-called "shihan" in jujutsu (his website also called it the "Gental Art," telling me that he, an American, can spell it correctly in Japanese but not in English). He said that "jitsu" means with weapons, while "jutsu" means without. Or was it the other way around?
Of course, this is pure rubbish, and anyone claiming the title shihan in any Japanese martial art should know better than that. Further, this goofy explanation of the difference between jutsu and jitsu was one of the bases for my conclusion that this guy was a complete charlatan and was probably not worthy of a green belt in any real jujutsu program.
The real difference between jutsu and jitsu is this: THERE IS NO DIFFERENCE. It's just a quirk of language.
See, the real word in Japanese is not pronounced "jutsu" or "jitsu" at all. It looks like this: 術, and is pronounced "jts". That's it. Jts. Now, if you were going to use the English alphabet to spell out a word that has no sounded vowells, how would you do it?
In Japanese, such words aren't unusual or particularly troublesome. As there's no hiragana character for just j, the Japanese use the character for "ji", combined with "yu" to form a "ju" or "jyu" sound. Either way, the "u" or "yu" isn't pronounced - only the "j". Likewise, the "tsu" comes out like "ts", again omitting the "u".
You can see how it would get confusing. But on our end, it's really quite simple. Many English transliterations of Japanese words use the letter u to assist with spelling and to fill out the word, thus the spelling jutsu. I can only assume that the spelling jitsu came from some attempt at pronunciation of jutsu.
In the case of Bazilian Jiu-Jitsu, you probably have to factor in some quirk of the Portuguese language as well.
But either way, you're not wrong. A word whose proper spelling contains no vowells at all can't easily be misspelled, can it? At this point, it's the meaning that stumps people.
See, jutsu doesn't mean art (although its original Chinese counterpart pronounced "shu" actually does mean art). It doesn't mean technique, either. Jutsu is actually a practical skill, whose study and application have taken on art-like qualities. I would liken the idea, as I understand it at this moment, to driving a car. Some people could call it an art, while others would say no such thing. But it's definitely a well-honed skill that has taken on some aspects of art-hood.