Extending from the Edge

Level: Intermediate

An X near the edge pushes back where the first block can start.

If there is an X near the end of a line, the first block must start beyond that X. When the starting position is pushed like this, the block's possible range narrows and overlap applies more strongly.

An X at the opposite end likewise limits where the last block can finish. Narrowing the range from both sides greatly reduces the freedom of the middle blocks.

This technique of narrowing the range one cell at a time from the edges can produce confirmed cells even on lines that seem to lack clues.

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