Treasures are scattered in the area. After finding them, you have to quickly return them to your hideout before the time runs out or before you get damaged. If ever you fail to do so, the treasure will return to its original location and you have to keep trying until you safely deliver it to the hideout. It will help clearing out the enemies along the way to make your job a lot easier.
#1. Meditation Turtle
Northwestern corner of the map, on the roof of a house near the cliff.
#2. Gyro Slicer 2000
First, you have to find the stone pillar on the northwestern corner of the map, near the safe's location. Interact with it and pull yourself back, then press X to spring up. Follow the ropes and you'll find this treasure in the end. Refer to the video below for more details.
#3. The Ninja Cookbook
On a boat east of the hideout and north of the Dragon Gates.
#4. Golden Teapot
After exiting from your hideout, turn to the left and continue to the bridge ahead. Look down and you should see this treasure.
#5. Jade Peach
Located southeast of the Sushi House
#6. Jade Samurai Helmet
Located southeast of the Geisha House
#7. Dragon Claw Statue
Required: Samurai Armor
The secret door housing this treasure is found in the upper level cavern that can be accessed by launching yourself from the springy branches in the northwestern corner, by the shinto gate. The door itself launches fireballs so deflect it with the samurai armor shield to open it. Refer to the video below for more details.
#8. Lucky Neko
Southwest of the hideout, top of a tall, stone pillar. You have to use the springy branches to reach it.
#9. Samurai Warrior
(Requires: Jailbird Costume)
Southeast of the hideout, under the bridge. You'll find cages there. Just push the cages aside to get this treasure.
#10: Golden Lion Statue
Requires: Archer and Sabertooth costumes
Head to the northwestern corner of the map and use the springy branches to reach the top of the rock tower. Create a rope bridge then reach the treasure door using the sabertooth costume's leap ability.
#11: Tales of the Samurai Hero Comic
Inside the time door south of the Sushi Shop
#12: Raccoon Daruma
Tales of the Samurai Hero Comic
Required: Archer costume
Head to the cliff west of the Safe's location and fire at the target to the north.