What this puzzle trains
This dense layout rewards precise chain reasoning and consistent follow-through.
This Expert #166 starts with 28 clues, has a score of 436, and mainly asks you to use Hidden Single / Claiming / Hidden Pair / Simple Chain / Naked Single.
Puzzle #166 sits near the middle of this archive and is a good check on how steady your routine feels.
Useful habits for this level
- Track chain logic with explicit reasoning.
- Return to Singles immediately after each major elimination.
After-solve notes
Individual puzzle pages are practice stops reached from the archive or strategy guides. After solving, keep these three notes so the next puzzle has a clear learning target.
- At the first stall, did you check "Track chain logic with explicit reasoning." before looking for Hidden Single / Claiming / Hidden Pair / Simple Chain / Naked Single?
- If you used a hint, write one target cell, elimination, or condition in your own words.
- Choose whether to continue at this level or read the related technique guide before returning.