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 exact rule the X-ray Coach applies

  • Missed-forced-mate rate: when the engine had a forced mate for you, how often your next move threw the win away.
courses.ts:170 (missedForcedMateRate)

Why it matters

A forced mate is the one situation where the right answer is objectively provable — missing it is a pure calculation failure, not a judgement call.