-MM1----------------------------------------------Cut Man:
Look inside the machine by Air Shooter.
-Fire Man:
It's in one of the Fire Trap tunnels by Ice Slasher.
-Metal Man:
It's hiding with the Presses over by Thunder Claw. You can see it from Magnet Missile.
-Shadow Man:
It's in one of the waterfall's grates between Leaf Shield and Fire Storm. Jump from Leaf Shield over to Fire Storm while looking to the right and you should see it.
-Pharaoh Man:
Near the teleporter inside the pyramid, on the right outside the gate, there's a Yashichi on the wall texture if you look down.
-Wave Man:
On the east side of the map near the Wave Bike tubes, dolphins occasionally pop out of the water. Every fourth time they come out in that spot, one of the dolphins will be a Yashichi.
-Junk Man:
There's a crack in the wall near the Big Health in the southern lava pool. Look down inside that crack to find it.
-Slash Man:
On the east side of the map with the Slash Claw by the trees, it's in the tree in the north-eastern corner. Just look up, shouldn't be too hard to find.
-Tengu Man:
In the tunnel leading to Homing Sniper, jump into the Wily Sign on the left and look up.
-Frost Man:
In the room with Ice Wave, it's in the window closest to the weapon. Jump and look down and you should see it.
-MM8 Wily Stage 1:
It technically has one in the pillar by Power Stone, but you can't see it without noclipping. Woops.
-Tengu Man B:
Use Tornado Hold on one of the platforms next to the weapon and it's in the top "ring" on the wall.
-Astro Man B:
In the scrolling wall next to Astro Crush, the Yashichi will occasionally scroll by.
-Dynamo Man:
On the west side of the map with the Fire Metools near the W Tank, jump past the fence into the pit and look to the right. It's in the top of the pink girders
-MM&B Wily Stage:
This one's hard to explain, so here's an image.
(https://i.imgur.com/uyn8qcn.png)
-Hyper Storm H:
There's a circular grate in the ground between Proto Buster and Flame Blast. Look down in there, and you'll see it.
-Tornado Man:
No words.
(https://i.imgur.com/3kYbtjo.png)
-Plug Man:
One of the static screens by the Laser Trident in the lower level will occasionally display the Yashichi.
-Galaxy Man:
In the skybox, there is a meteor with the Yashichi behind it. It will occasionally move up out from behind it. If you jump in the window near Wind Storm and look toward the Bunbi Catcher, it's pretty easy to spot.
-MM9 Wily Stage 1:
One of the Magma Dragon's fiery pieces will have a Yashichi inside it every six times it appears.
-MM9 Wily Stage 3:
I'm not sorry for this one.
(https://i.imgur.com/rS9sK3R.png)
(https://i.imgur.com/Z60wPAZ.png)