Here is the full list of all 44 Shadow Tactics: Blades of the Shogun - there are Aiko's Choice achievements.
Listen to everything Kuma has to say.
Fail the Shrine riddle at the beginning 3 times.
Come out of the other side of the river in Nagoya.
Find the perfect spot for sunbathing.
Talk to a samurai when disguised with Aiko.
Finish all missions.
Kill or knock out 5 guards at the same time with all 5 characters.
Kill a Samurai with a flower pot.
Kill 10 guards with Takuma's Sniper Rifle that are farther than 25 meters away from him.
Kill the Captain.
Collect 17 badges.
Kill at least 3 guards in the mission “A Night at Sea”.
Find all hidden caves in Hana Gakuen.
Kill Lady Chiyo with any character other than Aiko.
Kill a samurai with a rock.
Kill 30 guards with the help of the environment.
Kill 10 guards with traps in Hana Gakuen.
Finish “The Secrets of Hana Gakuen”.
Execute a plan with all 5 characters.
Hide with all characters in a single bush.
Kill Lady Chiyo without getting a disguise.
Finish the mission “Red Lights at Matsuyama”.
Don't extinguish any light sources in Matsuyama.
Finish the mission “The Best Laid Plans”.
Don't kill anyone with Takuma during the mission “The Best Laid Plans.”
Travel 1200 meters in water during the mission “The Best Laid Plans”.
Hide 150 bodies.
Distract 50 guards with Hayato's stone.
Kill 10 guards with a drop attack.
Kill 3 Samurai with Yuki.
Hide 100 bodies.
Finish the mission “A Night at Sea”
Distract 4 guards at the same time with Kuma.
Finish the mission “Reunion at Nagoya”.
Kill all enemies at the mansion in Nagoya.
Kill or knock out 150 guards.
Use Aiko's disguise 15 times.
Kill or knock out 100 guards.
Hide 50 bodies.
Kill 20 guards with Mugen's Swordwind.
Kill or knock out 50 guards.
3 times in one mission, kill 2 guards at once with Mugen's Swordwind.
Kill a guard with a drop attack from a rope.
Throw a guard into a well.