Omasa (於まさ, d. 1602) or Shōun-In (照雲院) was a Japanese woman from the Sengoku period. She was the first wife of Fukushima Masanori and daughter of Masanori's important retainer Tsuda Nagayoshi (津田長義). Omasa gave birth to Masanori's three sons. Her first son died as a baby for unknown reasons. Their second son survived but she died when giving birth to their third son due to birthing complications. Omasa was a naginata expert, she fought for herself several times and it was recorded that she participated in a military siege at Nagao castle.[1]