The identity of a killer. The whereabouts of a missing person. What happened the night before the hangover (recapturing lost memories).
There's going to be some overlap with this list.
Ichikawa's 'Inugami Clan' adaptation seems to have sparked a resurgence of the genre in the late 70s including a spoof from Nobuhiko Obayashi.
I'm not counting Confessions because the focus is on Takako Matsu's revenge rather than the detection of her daughter's killers.
Also ineligible: Detective Pikachu.