Even supposing that Ninkan had been studying when he was in Daigo Sanboin Temple before going into exile, still there was a too short period for him to initiate Kenren into the secret arts.
配流される前の、醍醐三宝院に在った頃から研究をしていたと考えても、見蓮に奥義を伝授するのに要した期間が短いことには変わりない。