The Mask Puzzle appears during the “What Lurks in the Shadows” mission in Onimusha: Way of the Sword. You will encounter it while exploring the Underground Laboratory, where the objective changes to “Solve the mask puzzle.”

When you enter the room, you will see four masks suspended above a locked container. Inside that container is the Unsettling Mask, an important key item needed to continue through the area.
What You Need to Do
You need to use Musashi’s Oni Bow to shoot the four masks above the locked container. However, shooting them randomly will not open the cage. They must be hit in a specific order.
The easiest solution is:
- Shoot the third mask from the left.
- Shoot the fourth mask from the left.
- Shoot the first mask from the left.
- Shoot the second mask from the left.
In short, the correct order is 3 → 4 → 1 → 2.
Count the masks from left to right while facing the wall with the locked container.
How to Discover the Correct Order
If you want to solve the puzzle yourself, look at the opposite wall. You will notice another set of the same four masks positioned within circular openings. Light shines through these masks, creating distinctive patterns.
Leave the main puzzle room and look at these masks from the other side of the wall. The light passing through the openings in each mask creates a different number of visible gaps or light shafts. These numbers provide the sequence for the puzzle.
The mask whose shadow shows one opening represents the first target. The mask showing two openings is second, followed by the mask showing three openings, and finally the one showing four openings.
Match each shadow to its corresponding hanging mask in the main room. This produces the sequence 3, 4, 1, 2.
How to Complete the Puzzle
Return to the room containing the four hanging masks and equip the Oni Bow. Face the masks and fire one arrow at each target in the correct sequence.
Start with the third mask, then hit the fourth. After that, shoot the first mask and finish by hitting the second.
When all four masks have been struck correctly, the locked container opens. You can then collect the Unsettling Mask.
What to Do With the Unsettling Mask
The Unsettling Mask is a key item rather than normal equipment. Once you collect it, you can use it to unlock a previously inaccessible door in the surrounding area.
Return toward the earlier section near the Spirit Mirror and look for the door mechanism that requires the mask. Place the Unsettling Mask into the mechanism to open the path and continue exploring the Underground Laboratory.
Mask Puzzle Solution at a Glance
For a quick reminder, follow these steps:
- Enter the Mask Puzzle room during “What Lurks in the Shadows.”
- Find the four masks above the locked container.
- Equip the Oni Bow.
- Check the matching masks and their light patterns outside the room.
- Count the openings shown by their shadows.
- Shoot the hanging masks from left to right in the order 3 → 4 → 1 → 2.
- Collect the Unsettling Mask.
- Use it at the nearby door mechanism to continue.


