Is Tetsujin 28-gou (2004) hentai?
English title: Tetsujin 28
No
Rated G (All Ages) on MyAnimeList and not tagged as Hentai.

TV · 2004 · 26 episodes · G - All Ages
Adventure, Drama, Historical, Mecha, Sci-Fi, Shounen
In post-WWII Japan, Prof. Shikishima has built up Shikishima Industries to be a technological powerhouse, working on developing robots. However, at the heart of their success lurks a dark secret from the war, something that cost the life of Prof. Kaneda, the mentor of Prof. Shikishima. Now Kaneda's son, Shoutarou, is about to learn the truth, and it will change him forever. (Source: ANN)
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