実

The word jitsu stands for reality and truth, often as part of the word shinjitsu (objective truth, an intangible thing). The word jutsu stands mostly for technique, in the sense of an art, a method, or even a spell. The words majutsu (for magic) and ninjutsu (for ninja arts/ techniques) are two examples.

I was glancing at a fan-translated chapter of Naruto (which I once read a decent amount to find out what I was missing, and then stopped for a while) and noticed “ninjitsu” being used. This isn’t a proper romanization. I realize a lot of people don’t really care; pronunciation has long gone the route of “ninjitsu”, even if it’s technically wrong. Make no bones about it: it is technically wrong. You wouldn’t know that if not for other words using the term jutsu, though.

Majutsu is a catch-all term for black magic. Houjutsu is, outside an RPG context (where the same pronunciation applies to white magic/ priest magic), a word for gunnery, as in, the huge cannons on battleships. Ijutsu is the practice of medicine/ healing arts. Renkinjutsu is alchemy, like in Fullmetal Alchemist. Kyuujutsu is Japanese archery (the Art of the Bow). Kenjutsu is Japanese fencing (the Art of the Sword). Finally, the broad term gijutsu means “technology”, a combination of “skill” and “art”. To a lot of people, there’s more than a little incomprehensible “magic” that rests in technology, too. 

If you’re just reading ninja stories, it probably won’t matter much. It’s only if you want to get into other cool Japanese things that you want to have some consistency and understand a little of the why re: why stuff’s called such-and-such. – J

“Shinobi” Comes From Somewhere

Now, very serious ninja fanatics may know, or suspect, that the word shinobi, used as a synonym for ninja (even by the Japanese), is derived from the verb shinobu (忍ぶ、しのぶ), meaning to hide (and also, to endure, but that is not the focus here).

Incidentally, ninja is 忍者, so the kanji for ninja is simply an “on reading” of the same kanji, whereas “shinobu” is from the “kun reading” (native Japanese) of the kanji.

Anyway, that’s not really the point.

忍び込む

This compound verb, shinobi komu, is a combination of “shinobu” and “komu.” The latter means, and this is my estimation more than any firm rule, to place / to insert. It is used in the sense of packing.

Combined with the shinobu verb, the dictionary will say that this means to creep in/ to steal in.

I would submit that there are even better ways to think of this: to infiltrate / to embed (oneself).

In other words, to infiltrate the enemy’s camp/ to embed oneself in the enemy’s camp.

This is a good and proper reading of the Japanese intent.

Cultural Relevance

This compound verb is used when someone has entered a place that ought to have been secure, and the occupants of that place are/ were caught unaware. Even if the infiltration is discovered, the term will still be used – in a past tense – to refer to what the intruder did.

This is not the same thing as an “internal spy” betraying; it means an outsider who has somehow managed to evade security.

Thus, this is very much a term that would be used in ninja contexts, as well as special forces, anime villains, and so on and so forth. The term gets around, and has such a nice and special ring to it that I consider it good to know. – J