Onimusha: Way of the Sword drops this puzzle on you in Chapter 11, "What Lurks in the Shadows," right when you're deep inside the Underground Laboratory at Nijo-jo Castle searching for Okuni's friend Hinagiku. The setup is deceptively simple: four masks, a bow, and no obvious instructions. The good news is that the solution is right in front of you once you know where to look.
Where is the mask puzzle located?
The puzzle sits in Underground Laboratory Level Three. You reach it after Dyoko tasks you with finding a key to the Underground Laboratory Door. Along the way, you'll open two doors sealed with red strings, then locate the Level Three Spirit Mirror. The mask puzzle room is just past that point.
What does the mask puzzle involve?
When you step inside, four masks hang from the ceiling on threads. Those same four masks are also mounted on the walls near the entrance, each lit by a spotlight from above. Your job is to shoot the hanging masks with your bow in the correct sequence to remove the Unsettling Mask and open the path forward.
The puzzle doesn't hand you the order directly. You have to earn it.
What is the correct arrow order for the mask puzzle?
After testing every combination and cross-referencing the shadow hole counts, here's the order that solves the puzzle:
So the sequence goes: third, fourth, first, second.
The numbering follows the physical order the masks appear hanging in the room. Take your time lining up each shot. There's no timer, so accuracy matters more than speed.
Onimusha: Way of the Sword Mask Puzzle Solution
What happens after you solve the mask puzzle?
Once you nail the sequence, head straight into the room and interact with the Unsettling Mask to dismantle it. That clears the obstacle blocking your path deeper into the Underground Laboratory.
The puzzle itself is straightforward once the shadow mechanic clicks, but the game gives you zero guidance on where to look for the clue. That's the part that catches players off guard, not the execution.
Onimusha: Way of the Sword Mask Puzzle Solution
Getting more out of Nijo-jo Castle
The mask puzzle is one of the more memorable moments in Chapter 11, but the castle has plenty more to offer. If you want to make sure you're equipped before heading deeper, check out the full Oni Armament locations guide to confirm you haven't missed any upgrades. All 6 Oni Armaments are scattered across the game, and having them before the later chapters makes a real difference.
For everything combat-related, the Onimusha: Way of the Sword combat guide covering Parry, Issen, and more breaks down every core mechanic so you're not walking into the Underground Laboratory's tougher encounters underprepared.
And if the enemies in this chapter are giving you more trouble than the puzzle itself, the complete boss guide for all encounters covers phase strategies and counter tactics across all 18 fights. Find all of that and more in the full Onimusha: Way of the Sword guides collection.