840 multiple-choice video questions from 76 public video benchmarks, one item per video, four capability groups x 210 (Perception, Temporal, Spatial / physical, Reasoning / knowledge). The set is the difficulty-first census of the BenchCheck screened pool: items that none of the cheap attackers of the pool screening (text-only, single frame, 32-frame 2B model, options-only, shuffled frames) could solve, ranked by the worst-case attacker percentile, with the marked answers verified against the frames; no cap on any model's accuracy (v6, 2026-09-19: the earlier v5 composition capped the reference model's share of correct answers at 45 %, the cap is dropped so that every row of the leaderboard…