A "포인팅 페어" strategy applies when a candidate within a 3x3 block appears only two times, and both instances fall on the same row or column. 이것은 의미합니다 the solution for that candidate within this block must be in one of those two cells. 따라서, you can remove that candidate from the 메모 of all other cells in that row or column outside of the block.
To better understand "포인팅 페어", let's look at an example.
살펴봅시다 the top-left block. All the cells that could possibly contain the number 4 are in a single column. Since the number 4 must appear at least once in this block, one of the highlighted cells must contain the 4.
From this, we can safely eliminate the possibility of 4 being in any of the other cells in this column.
Remember that you can use the same technique for blocks, rows, and columns.
이것은 the "포인팅 페어" solving method. Now you can move on to the next 스도쿠 strategy below, "포인팅 트리플."