If you’re playing Hollow Knight: Silksong and want to unlock the Second Sentinel, you’ll first need to collect three Cogheart Pieces. These fragments are hidden in different bell puzzle rooms across the map, and once you’ve gathered all of them, they’ll combine into a Cogwork Heart. You can then use this heart to awaken the Second Sentinel and progress the story. The puzzles themselves aren’t too hard, but you’ll need to strike the bells in the exact order, so having good timing and memory is key.
Where To Use All 3 Coghearts in Hollow Knight Silksong
Once you’ve gathered all three Cogheart Pieces, they’ll automatically merge into a single Cogwork Heart. To put it to use, head over to the Cogwork Core on the western side of the map, just to the left of the Bench. Inside, you’ll come across a huge inactive automaton. Place the Cogwork Heart into it, and this will bring the Second Sentinel to life.
How To Get All 3 Coghearts in Hollow Knight Silksong
In Hollow Knight: Silksong, Cogheart Pieces are special items you’ll need to find. Collecting all three will automatically form a Cogwork Heart, which is then used to power up the Second Sentinel and move the story forward. Each piece is hidden away in a bell puzzle room, and to unlock them, you’ll have to strike the bells in the right order.
Choral Chambers – First Cogheart Piece
You will find the first Cogheart Piece in the Choral Chambers. Before heading deeper toward the Slab, climb into the room above. You’ll need to clear a vertical shaft filled with enemies, and at the top you’ll see the fragment waiting on a ledge.
To claim it, you’ll need to solve two bell sequences:
- For the first sequence, strike bell 3, then bell 6, followed by bell 5, then bell 1, and finally bell 7.
- For the second sequence, hit bell 2, then bell 4, followed by bell 6, bell 3, bell 5, and end with bell 1.
Finish both patterns correctly, and the first Cogheart Piece is yours.
Whispering Vaults – Second Cogheart Piece
The second piece is hidden in the Whispering Vaults. Work your way through until you reach the upper platforms, then look for a small, tucked-away alcove. You’ll need the Cling Grip ability to scale the walls safely and reach it.
This time, there are three bell puzzles to solve:
- The first sequence goes bell 1, bell 2, bell 7, then bell 4.
- The second sequence is bell 7, bell 5, bell 6, bell 4, and back to bell 5.
- The third sequence starts with bell 2, then bell 7, followed by bell 3, bell 5, bell 6, and ends with bell 1.
Get all three right, and you’ll earn your second Cogheart Piece.
Memorium – Final Cogheart Piece
The last Cogheart Piece is tucked away in the Memorium, a secret area to the right of the elevator inside the Cogwork Core. To reach it, you’ll need precise platforming and the Clawline ability to swing across the gaps. Once inside, waves of Pilgrim enemies will attack, and you’ll need to defeat them before the puzzle becomes available.
The bell puzzle here has three sequences:
- First, hit bell 6, then bell 5, then bell 4, and finally bell 3.
- Second, strike bell 4, bell 5, then bell 2, go back to bell 4, and finish with bell 1.
- For the last sequence, start with bell 2, then bell 7, followed by bell 3, bell 5, and end on bell 1.
Once you solve these, you’ll have your third and final Cogheart Piece.
