Rasengan is the one Naruto jutsu name VIZ never seriously tries to translate outright, and the corpus shows exactly why: the word had already become the technique's brand by the time it needed an English readership. But localization strategy wasn't fixed from day one. The very first combat shout the corpus captures, Vol. 21 p.134 ("螺旋丸！！"), doesn't just print RASENGAN — it stacks a full literal gloss underneath it, "SPIRAL CHAKRA SPHERE!!", as if the translator wasn't yet confident the bare romaji would land with readers. The identical gloss recurs in Vol. 23 and Vol. 29. By Vol. 36 — the training arc where Naruto and Jiraiya reverse-engineer how Minato actually built the move — VIZ has fully committed to plain "RASENGAN!!", no translation, no hyphenation aid. The gloss never returns for the rest of the manga, including all of the compound variants (Super Ōdama Rasengan, Wind Style Rasengan, Sage Rasengan, Planet Rasengan, Biju Rasengan, Magnet Style Rasengan) that stack modifiers onto the same bare noun in Parts I and II.
That naming discipline is doing real narrative work. Because VIZ never re-translates or re-glosses "Rasengan" after Vol. 36, every subsequent variant reads as a modification of one fixed, familiar word — Super Ōdama RASENGAN, Wind Style RASENGAN, Sage RASENGAN — rather than a new technique with a new name. The corpus captures the Vol. 35–36 chapters explicitly theorizing about this in-fiction: Kakashi tells Naruto that Rasengan is a jutsu built purely on shape manipulation ("形態変化") with no nature-chakra component, which is precisely why it's compatible with so many elemental prefixes later on — wind, sage mode, magnet release — without ever needing a new base name.
It's also worth noting how much of the corpus's 72 occurrences are ABOUT Rasengan rather than shouted mid-battle: the earliest hits (Vols. 18–19) are Orochimaru and Jiraiya arguing over who taught it to Naruto and whether a genin should even be attempting it, establishing the technique's reputation for danger before the reader ever sees it thrown. That's a deliberate hype structure — Rasengan gets talked about for roughly three volumes before Naruto ever completes one on-page.