Power Stones are the material that pays for Musashi’s core combat kit in Onimusha: Way of the Sword. Reflex Combo, Chain Issen, Deflect, Blazing State, Petrify, Flat-Out Sprint and most of the Oni Bow upgrades all bill you in Power Stones at the Spirit Mirror, and you need every one of those upgrades bought for the Well-Rounded trophy and achievement.
Quick answer: There are 54 Power Stones. 23 sit in world chests you have to open yourself, and the other 31 are handed to you for finishing missions, Oni Portals, Chance Encounters and Mysteries of Kyoto. One playthrough yields enough Power Stones to buy every skill upgrade, so clear the chest list below before the point of no return ahead of the final mission, “The Clash At Rendaino.”
Unlock Oni Vision: Treasures before sweeping the map
Chests holding Power Stones only show up reliably once your detection skills are online. Spend your early Oni Stones on Oni Vision: Treasures, then Oni Vision: Treasure 2 after the 1st Oni Portal, then Oni Vision: Search Range after the 2nd Oni Portal. With all three, hold L2/LT and tap R2/RT repeatedly while you move and the treasure markers populate as you walk.
Marked chests stay on your map, so you can scan an area now and come back later. Open the map, highlight a Treasure point and set a marker on it if you plan to return with a better route or a fast travel unlock.
Power Stone chest locations
These 23 stones sit in chests. Nothing here is missable, but a few are gated behind traversal skills or barriers, so a second pass late in the game is usually faster than forcing them early.
Oni Refuge, Kyoto and the Underground Laboratory
| Stone | Chest location |
|---|---|
| #1 | Oni Refuge, on a small island. Look between your side and the island for a collapsed bridge and shoot it with an arrow to raise it, then cross and open the chest. |
| #7 | Small courtyard southeast of the Kamo River – East Spirit Mirror in Kyoto. |
| #8 | Underground Laboratory on Underground Level 3. |
| #13 | The west island of Kyoto. |
| #22 | Southwest of the Gojo Street – West Spirit Mirror. |
| #28 + #29 | The arena where you fight Sasaki Ganryu, next to the Yasaka Pagoda Spirit Mirror. |
| #44 | North of the Higashioji Street Spirit Mirror. |
| #45 | Just outside Yasaka Shrine, to the south. |
Kiyomizu-dera Temple and the slope
| Stone | Chest location |
|---|---|
| #9 | Inside Kiyomizu-dera Temple, behind a Malice Barrier. |
| #10 | North of the Kiyomizu-zaka Slope Spirit Mirror. |
| #18 | Kiyomizu-dera Temple, down the path behind the Oni Wall. |
Mount Oe
| Stone | Chest location |
|---|---|
| #36 | The Valley. After shifting the platforms around, go back to the platform you wall ran on, drop down and follow the path to the chest. |
| #37 | The same room as the Storehouse Spirit Mirror. |
Arashiyama
| Stone | Chest location |
|---|---|
| #48 | In the bamboo grove. |
| #49 | The north end of the swamp. |
| #50 | Elsewhere in the swamp. |
| #53 | The dead end of the village west of the Hozu River Spirit Mirror. |
| #54 | Northwest of the Sandbar – Near Stage Spirit Mirror. |
Hidden Oni Treasure chests with Power Stones
Two of the Hidden Oni Treasure chests pay out in Power Stones. Hidden Oni Treasure #3 contains Power Stones #34 and #35, and Hidden Oni Treasure #4 contains #42 and #43. Each one is found by matching the location drawn on the corresponding Old Drawing to a spot on the map, then digging the chest out at that exact point.
Power Stones from missions and Oni Portals
These 17 arrive automatically as you push through the campaign and clear the Oni Portals. You do not need to search for any of them, but the list is useful for checking which stones you should already own at a given point.
| Stone | Reward for completing |
|---|---|
| #2 + #3 | The Silent Gauntlet |
| #4 | Careful What you Wish For |
| #5 + #6 | Windswept Kennin-ji |
| #11 + #12 | Bloodbath on the Bridge |
| #14 | The 2nd Oni Portal |
| #15 | Shadows Fall |
| #23 | A Tempest at the Temple |
| #30 + #31 | Okuni’s Kabuki Dance |
| #32 | The Demon on the Mount |
| #33 | The 3rd Oni Portal |
| #38 + #39 | A Haunted Distraction |
| #46 + #47 | Storm Chaser |
| #51 + #52 | The Clash at Rendaino |
Note: #51 and #52 land with the final mission itself, so they arrive after you have already spent everything else. Buy your remaining upgrades before that if you want the trophy to pop earlier.
Power Stones from Chance Encounters and Mysteries of Kyoto
Side content covers the remaining 14. These are the stones players most often finish the game without, because the encounters are easy to walk past while chasing the story.
| Stone | Reward for completing |
|---|---|
| #16 + #17 | A Wife’s Prayer (Mystery of Kyoto) |
| #19 + #20 | Ace Archer: Nijo-jo Castle (Chance Encounter) |
| #21 | An Ugly Business (Chance Encounter) |
| #24 + #25 | The Growling Ghost (Chance Encounter) |
| #26 + #27 | Ace Archer: Kyoto Imperial Palace (Chance Encounter) |
| #40 + #41 | The Night Parade (Mystery of Kyoto) |
Cleanup window and how to confirm you have them all
Free roam stays open right up to the point of no return before “The Clash At Rendaino.” Keep a manual save there and you can mop up every chest and side activity from that point. Even after the credits, choosing Continue from the main menu drops you back before the final mission.
The confirmation you want is the Well-Rounded trophy and achievement, which requires every basic and special skill learned and fully upgraded through the Spirit Mirror’s “Enhance Equipment/Abilities” menu. If Well-Rounded has not popped and every Power Stone upgrade is bought, the shortfall is on the Oni Stone side. A single run does not produce enough Oni Stones to max the Gauntlet, and skills carry into New Game+, so the last upgrades are finished on a second run.
One planning detail matters for that second run. Mysteries of Kyoto and Chance Encounters reset in New Game+, which means every stone tied to them can be earned again. Enhanced skills, Genma Notes, Charms, Hozuki Pouches and Lion Dogs all carry over, so nothing you have already bought is lost.
