Here is the full list of all 43 Shigatari achievements.
Decapitate a boss with a single blow
Master the judan stance
Defeat a demon
Beat the game with courage
Beat the game on easy difficulty
Beat the game on normal difficulty
Master the gedan stance
Gain the demon's power
Master the hasso stance
Master the stance mastery
Defeat the chudan master
Have one thousand coins
Master the waki stance
Forge the legendary sword Masamune
Drink gaijin sake with gaijin weapon and armor equipped
Defeat the Stance Master
Visit three bridges in a single region
Defeat the Hasso Master
Defeat the Gedan Master
Defeat the Waki Master
Master the chudan stance
Defeat the Weapon Master
Defeat the judan master
Beat the game on hard difficulty
Master the weapon mastery
Eat 10 pieces of sushi
Drink 10 jars of sake
Beat the game on hard with no ancestor favor spent
Complete three regions without fighting any women
Complete three regions without fighting any men
Show up late to a duel, then win with a bokken
Beat the game only changing weapons once
Change clothing during combat without dying
Beat the game with sincerity
Beat the game with cunning
Beat the game with prudence
Beat the game with grace
Beat the game with brazen
See every ending
Beat the game killing only six people
Complete five regions without saying "Die"'
Complete five regions saying "Die." at every opportunity
Meditate under a waterfall with hachimaki and salt