Here is the full list of all 11 Tale of Ninja: Fall of the Miyoshi achievements.
Successful killed Sogō Kazumasa
Killed Sogō Kazumasa by his historical way
Killed Miyoshi Yoshikata
Use the gun to complete the mission
Finished the Akutagawa Hill Castle level
Killed Miyoshi Yoshioki with poison
Killed Atagi Fuyuyasu
Get help from Matsunaga Hisahide
Finished the final mission