In Hollow Knight: Silksong, the three Cogheart pieces are one of Pharloom’s best-kept secrets. As of 2026, this little scavenger hunt still hasn’t changed in the latest build, so players can follow these steps without worry. The game barely drops a hint about what they do, so plenty of players end up running around like a headless chicken trying to figure out if the pieces are even worth the trouble. For completionists, though, these gears are the real deal—they unlock a secret side quest and a special boss encounter. This guide breaks down every Cogheart piece location and how to use them, no fluff, just the good stuff.

Cogheart Piece Location #1: Choral Chambers

The first Cogheart piece sits on the west side of the Choral Chambers. Once players reach the spot shown below, they will bump into a bell puzzle where the bells have to be rung in a specific order. Missing a note means backtracking, so it is smart to pause and check the pattern before going ham on the bells.

Using a number label for each bell, the correct sequences are:

• Sequence 1: 1, 5, 4, 6

• Sequence 2: 3, 6, 5, 1, 7

• Sequence 3: 2, 4, 6, 3, 5, 1

After completing the bell puzzle, the first Cogheart piece is in the bag. Then it is time to head toward the Whispering Vaults.

Cogheart Piece Location #2: Whispering Vaults

The second piece lurks in the southwestern part of the Whispering Vaults. This area serves up another bell puzzle, and the pattern here is a little more twisty than the first one.

The solution to the Whispering Vaults bell puzzle is:

• Sequence 1: 1, 2, 7, 4

• Sequence 2: 7, 5, 6, 4, 5

• Sequence 3: 2, 7, 3, 5, 6, 1

After ringing that final bell, a platform rises from the ground. Players should interact with it to claim the second Cogheart piece.

Cogheart Piece Location #3: Memorium

The last piece can be found on the eastern side of Memorium. Heads up: Memorium can only be accessed once the player has unlocked the double jump ability, so anyone who has not grabbed that yet should circle back later.

No surprise here—there is another bell puzzle waiting in Memorium. The correct order is:

• Sequence 1: 6, 5, 4, 3

• Sequence 2: 4, 5, 2, 4, 1

• Sequence 3: 2, 7, 3, 5, 6, 1

Just like the other bell puzzles, solving this one raises a platform that holds the final Cogheart piece.

How to Use the Cogheart Pieces

After collecting all three Cogheart pieces, players can use them to activate the Second Sentinel in the Cogwork Core. The exact location is shown below, marked by the red arrow.

Once players inspect the device and insert the Cogheart pieces, the Second Sentinel is freed. After that, they should explore the Choral Chambers to find the Second Sentinel fighting enemies in different locations. Its appearance is random, so thorough exploration is the name of the game. Players should keep searching until they have seen the Second Sentinel fight enemies twice.

After witnessing the Second Sentinel in combat twice, players need to return to Songclave. There, the Final Audience side quest will show up on the Wish Board. The Final Audience wish tasks players with hunting down the Second Sentinel and defeating them in a boss fight. It is a proper scrap, so players should sharpen their needle, stock up on tools, and make sure their crest loadout is ready before picking that fight.

In short, the Cogheart pieces are a bit of a trek, but the secret boss and side quest make the hunt worth it.

Once the Final Audience is cleared and the Second Sentinel is no longer a threat, players can finally breathe and take in everything the game has left to offer. Between chasing remaining lore fragments, refining their loadout, and revisiting areas with newly unlocked abilities, there is no shortage of post-quest content to sink time into. The hunt for the Cogheart pieces may be over, but the sense of discovery it sparks tends to carry over into every corner of the map it unlocks.

For players who enjoyed this kind of hidden-content scavenger hunt, plenty of similar action RPGs are worth exploring next. Whether you are picking up a DLC for the same title or eyeing a fresh adventure with equally cryptic puzzles, it never hurts to compare costs before pulling the trigger. A quick trip to check game prices can help you stretch your budget further, so you can keep the momentum going without burning a hole in your wallet.