Talk:Hideyoshi Nagachika/@comment-29781768-20180320180553/@comment-2001:14BA:16FA:9400:AD0E:2354:4CFE:C326-20180320183442

It was in one of the final chapters of the original Tokyo Ghoul manga. Basically Kaneki gets critically injured by Amon and crawls down into a sewer while still in his deranged half-kakuja state. There he encounters Hide and blacks out soon after.

Moments later he wakes up in a different part of the sewer with his wounds gone and a taste of blood in his mouth. Turns out he regenerated by eating his face.