Kotaku reports that adjustments are being made to the Japanese release of Fallout 3 to remove or tone down certain elements.<blockquote>The side-quest The Power of the Atom has been changed. Non-playable-character Mr. Burke has been taken out of this side-quest, removing the option of detonating the nuclear bomb. That's not all, the name of a weapon was changed as it was deemed "inappropriate" for Japan. Smart money says the weapon is mini-nuke launcher "Fat Man" for obvious reasons. The online reaction from the Japanese users seems to be largely disappointment to these edits. Fallout 3 goes on sale in Japan this December.</blockquote>If I read the translation of the press release right, there will also be no dismemberment of humans or named ghouls, while feral ghouls, super mutants and beasts will still fly apart and there is no (other) reduction in gore.
Link: Bethesda press release (in Japanese)
Link: Auto-translated version (not in Japanese)
Spotted at N4G.
Link: Bethesda press release (in Japanese)
Link: Auto-translated version (not in Japanese)
Spotted at N4G.