数独中的1-5-9规则是什么？
最后更新
1-5-9规则不是官方的数独技巧，而是一种实用的扫描习惯。经验丰富的解题者通常先放置数字1，然后是5，再是9，然后才是其他数字——因为这三个数字的消除效果最有效。
为什么是1、5和9？
The three digits represent the low extreme (1), the midpoint (5), and the high extreme (9) of the digit range. Because these values are visually distinctive when scanning across the grid, many solvers find them easiest to track simultaneously across multiple units. Placing them first tends to open placements for adjacent values through standard elimination.
如何应用它
Start by scanning all rows, columns, and boxes to find every empty cell where only the digit 1 is possible - A naked single for 1. Then do the same for 5, then 9. After these three passes repeat for 2 and 8, then 3 and 7, then 4 and 6. By the time you reach 4 and 6, many cells are already filled and remaining placements are easier to find.
这是真正的技巧吗？
No - It is a heuristic, a rule of thumb that speeds up scanning for some solvers. It creates no new logical deductions. Any scanning order will eventually find all naked and hidden singles. The 1-5-9 rule provides a repeatable starting pattern that helps beginners avoid getting lost in a blank grid - Nothing more, nothing less.