A depressingly short list of old man yaoi. Both characters need to be 40+, or at least darn close to 40 - not just one old man x one younger man age gap romance (not that I don't love that too, but it's not old man yaoi imho). No, 40+ isn't "old" by any objective measure, but even finding stories like that is hard, if we make it actual old man yaoi, it'll be even harder.