In six moves the engine's first choice was a dark-squared bishop move four times, and each time you played something else — by the time the bishop was finally traded, it was on Black's terms and it cost a pawn.
Nothing you played before move 10 was flagged. The game was decided by one recurring question you kept answering with a different move.
10.Bxc6 — the wrong bishop
Forty-three seconds, and the position went from -0.9 to -1.6. Bxc6 gives up the bishop that had a job for a knight that was about to be traded anyway, and the recapture bxc6 hands Black the open b-file and a pawn chain that makes d5 permanent. The line ran Qd3 Bxf3 Qxf3 Qb6 Qd3.
The engine wanted the other trade: Bxe7 Nxe7 Bd3 Nc6 Nb5 Be7 — the g5 bishop for the e7 knight, the light-squared bishop dropping back to d3 where it has a diagonal, and b5 poking at c7 and d6.
The test isn't which capture is available. It's which of your minor pieces has the worse next ten moves. With Black's pawns on d5 and e6, that was the dark-squared bishop, and it was the one that stayed.
13.Bh4 — the same trade, now offered to you
Thirteen seconds, -0.3 to -2.2, and the biggest swing in the game. James's 12...h6 had just given the position back to nearly level and asked the bishop a question. Bxe7 Qxe7 Na4 Rab8 c3 Qf6 answers it and holds the balance. Bh4 keeps a bishop that now has one diagonal and no targets on it, and what it allowed was Qb6 Bg3 Bxg3 Qxg3 Nf5 Qd3.
The next move sharpens the point. 14.Qd3 took eighty-seven seconds — the longest think of the game — and the engine's move there was Bg3: same bishop, same question, third time of asking.
15.Na4 — the knight follows the bishop offside
Fifteen seconds, and -2.8 became -4.6. Na4 puts a knight on a square Black's queen is already looking at, and what it allowed was Qa5 Bf6 Qxa4 b3 Qb5 c4. Bg3 was still the move — Bg3 Nxg3 fxg3 Qxb2 Ne2 Qb5, taking the trade and accepting that b2 goes with it.
You did play Bg3 eventually, at move 18. By then the recapture fxg3 was forced and 19...Bxg3 picked up the pawn: the same trade, three moves later, on the worst available terms.
Phase notes
Opening: nothing flagged, and the position was still around -0.9 by move 10. In an Exchange Caro-Kann as White that is already the wrong side of level, which is worth a look on its own.
Endgame: 24.a3 in an already-lost position, forty-six seconds, -3.7 to -5.3. It gave the bishop something to bite on — c4 bxc4 Rxc4 Kf2 Bxa3 Rb1. When you're worse, a pawn move on the side where his bishop lives is a hook, not a defence.
Profile check
A new item, and it is the whole game: a minor piece with no good square is a piece to trade, not a piece to reposition. That is separate from the reply-check habit already in your file, though that one showed up too — 15.Na4 stepped onto a square the black queen was covering. The old pattern of long thinks producing the loose moves also held: forty-three seconds on 10.Bxc6, eighty-seven on 14.Qd3.
What to drill next
- The position before 13.Bh4 — find Bxe7 and play out Bxe7 Qxe7 Na4 Rab8 c3 Qf6. Beat the engine from here three times running.
- Caro-Kann theory and explorer — the Exchange gave you nothing here, and no single move was to blame for that.
- Hanging-piece puzzles — for the 15.Na4 shape.
Before you reposition a minor piece, ask whether the position is offering to trade it — and if it is, take the trade the first time it's offered.