Sadatsugu was a Japanese swordsmith. Was called Uemonnosuke. He was well known as swordsmith in the service of ex-Emperor Gotoba. Around 1336, another swordsmith bearing the same name lived in Bitchu Province. He was also famous, his full name being Osumi-Gonnosuke Sadatsugu Taira.
Sadatsugu was born in 1190 Okayama, Japan. Son of Moritsugu.