His older brother Shinnojo and his adopted parent Masatsugu TSUCHIYA joined the Battle of Nagashino in 1575, died on front lines, but Nagayasu did not participate in the battle.
1575年の長篠の戦いでは、兄の新之丞や寄親の土屋昌次は出陣して討死しているが、長安は出陣していない。