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SOLO-036 · Othello / Reversi

EXTREME

The Last Word

White plays. Find his only best first shot and the final differential that he can guarantee against any optimal defense.

Materials: Pencil, gum; tray 8 × 8 and optional reversible pions.

Rules you need

The puzzle

Trait: White. There are 11 empty boxes left.

For the evidence, also give the best defense after your first blow, then examine the other legal blows. No second person is necessary: analyze both sides on paper.

Coordinates: lines from top to bottom, columns from left to right.
L / CABCDEFGH
1·N·NNN··
2·NBBBBB·
3BNBBBBBN
4BNBNBNB·
5BNBBBNB·
6BNBBBNBN
7BNNNNNNN
8··BBB·BN
Why this level?

End of part requiring a ramified defense shaft on ten or eleven boxes, with possible beating orders, mobility and passes. It is necessary to combine retrograde calculation, control of adverse responses and exact comparison of alternatives; no local corner or immediate majority rule is sufficient. Editorial evaluation based on the required techniques; not calibrated by a human panel.

Your workspace

Write down your assumptions separately from deductions you have proved.