Coach definition, not a live verdict. These pages show how the X-ray Coach defines this concept and where its thresholds sit, sourced from the coach's own code. Unlike the tactic pages, nothing here runs a live detector — example boards illustrate the rule, they don't execute it.
What it means
- The coach flags when a move *creates* doubled pawns — for your side, and for the opponent's side (using the engine's recommended reply, since the doubling depends on which recapture lands).
- Each event is classified by outcome, so 'doubled pawns' is never treated as automatically bad — the engine's verdict decides.
The exact rule the X-ray Coach applies
- Self-side and opponent-isolated events fire on the same ply via a 1-ply set-delta (the structure changed this move). Opponent-doubled uses a 1-ply look-ahead onto the engine's PV-best reply.
- Outcome classification: created-ok (engine endorsed), created-avoidable (engine had a cleaner alternative), created-voluntary (a clean recapture was available but you doubled anyway), missed (engine recommended doubling), avoided-smartly, irrelevant, unknown.
- Whether two same-file pawns count as 'tight' uses a file-gap test (gap ≤ 2) implemented in the Rust chess_core labeler.
Why it matters
Doubled pawns can be a weakness (less mobility, harder to defend) or a strength (open files, central control) — the coach scores the *decision*, not the structure in isolation.
Example
the highlighted pawns
After …cxd4: White's d2 and d4 pawns are doubled on the d-file. The e3 pawn means neither d-pawn is also isolated. (Position from the coach's own moveEvents test fixture.)