Uesugi Kenshin invaded Noto twice in 1576–77 and besieged the 'impregnable' Nanao Castle. Unable to storm it, he took it in the ninth month of 1577 through the betrayal of the pro-Uesugi retainer Yusa Tsugumitsu, killing the anti-Oda commander Cho Tsugitsura and his kin. Riding the momentum, he routed Shibata Katsuie's Oda relief army at the Battle of Tedorigawa — one of the few clear victories of Kenshin over Nobunaga's forces. He is also said to have composed in camp the famous poem 'Frost fills the army camp, the autumn air is clear...' (though its authorship is disputed).