Published catalog report · July 2026
July 2026 Sudoku difficulty report.
A reproducible engine-fact summary of the 60 puzzles in the published catalog batch dated 17–31 July 2026. This is not a player study or a full natural-month observation.
Scope and source
– · 15 dates · 60 puzzles
legen-sudoku-engine/1.3.0
legen-ldi/v0/sha256:f541ca7389fce1f8257d6051209f234ddcd83980c1834ea29c078e6af58e0dd7
Daily catalog SHA-256: c74d7ff54917d88a00cddd452b05764149f9a1baefc856e79a7e65d4576fbb26
Headline facts
- Puzzles / dates
- 60 / 15
- LDI min / median / max
- 0 / 21.5 / 95
- Logical steps min / median / max
- 49 / 55 / 65
- Highest observed technique
- XY-Wing
LDI and logical steps by assigned tier
| Tier | LDI min / median / max | Steps min / median / max |
|---|---|---|
| Easy | 0 / 9 / 14 | 49 / 53 / 57 |
| Medium | 15 / 19 / 21 | 51 / 53 / 57 |
| Hard | 22 / 24 / 35 | 53 / 55 / 58 |
| Expert | 39 / 68 / 95 | 53 / 62 / 65 |
Hardest-technique counts
- Hidden Pair5
- Hidden Single37
- Locked Candidates6
- Naked Pair2
- Naked Single3
- XY-Wing7
Five highest-LDI puzzles
LDI0-0a49699ec02f55dac179fe08d81a5a32739ada01LDI 95 · 65 steps · XY-WingLDI0-17ab0fdee343d133f6081557667d6e21c105c133LDI 87 · 62 steps · XY-WingLDI0-1399d1cd52c5113e0b92f011f45986f36505cae7LDI 85 · 63 steps · XY-WingLDI0-07c296b8e4ff384332ad2017fd093e174b9e9ea3LDI 75 · 65 steps · Hidden PairLDI0-16fa737582509950ea3769f3ef1474f7fd505691LDI 75 · 65 steps · Hidden Pair
Interpretation limits
- The four difficulty tiers each contain exactly fifteen puzzles by publication design, so tier counts are not a natural population distribution.
- The period covers the published catalog batch from 2026-07-17 through 2026-07-31, not player activity or a full natural-month observation window.
- No completion-time, hint, error, region, account, or other player-behavior data is used.
- Results describe the fixed engine and LDI versions shown in this report.