Following are some calligraphy confirmed as genuine; Yatsushiro Municipal Museum keeps "Nagaoka Okinaga ate shojo" (Letter to Okinaga NAGAOKA); Yoshikawa Eiji House and Museum keeps "Arima Naozumi ate shojo" (Letter to Naozumi ARIMA); Kumamoto Prefectural Museum of Art keeps "Dokkodo" (means 'the way of walking alone'); Matsui-Bunko Incorporated Foundation keeps "Senki" (means 'spirit of fight').
書としては、「長岡興長宛書状」（八代市立博物館蔵）「有馬直純宛書状」（吉川英治記念館蔵）「独行道」（熊本県立美術館蔵）「戦気」（松井文庫蔵）が真作と認められている。