His writings 'Harutoyo-ko Ki' (Harutoyoki) (Nichinichiki) has many articles on Nobunaga and the revolt at Honno-ji Temple and therefore it is deemed to be material that has high historical value.
その著書「晴豊公記（晴豊記）（日々記）」は信長や本能寺の変に関する記述も多く、史料価値が高い一級史料とされている。