外部数独
72
39
85
94
15
87
56
13
74
76
19
32
34
29
15
98
61
32
6
3
5
1
1
4
6
3
2
3
5
4
1
9
7
4
7
9
5
8
3
5
2
4
8
9
9
7
5
3
2
6
6
1
9
8
2
1
14
32
76
25
46
79
23
85
91
63
54
12
21
97
53
89
47
16
如何玩外部数独
标准数独规则适用。每个显示在网格外的数字必须出现在该行或列的前三个单元格中（最近的3x3宫）。左侧/右侧的蓝色线索指该行的前/后三个单元格；顶部/底部的蓝色线索指该列的前/后三个单元格。
完整指南 →
Grid 外部的 Digits 必须出现在该 row 或 column 的前三个 cells 中
什么是外部数独？
外部数独将数字放在网格的边距中。每个外部数字必须出现在它指向的行或列的前三个单元格（最近的宫）之一。网格内部不提供标准的已知数字——所有线索都来自边距。这创造了一种不寻常的数独形式，其中初始约束完全来自网格外部。
一览
| 约束类型 | 外部线索 |
| 典型给定数 | 28–36 given + 4×9 outside clues |
| 难度评级 | ★★★☆☆ 3/5 |
| 平均解题时间 — 简单 | 8 分钟 |
| 平均解题时间 — 中等 | 18 分钟 |
| 平均解题时间 — 困难 | 36 分钟 |
| 平均解题时间 — 专家 | 65 分钟 |
如何解外部数独
| 技巧 | 它的作用 | 级别 |
|---|---|---|
| Clue-Zone Mapping | Each outside digit must appear in the nearest 3 cells of its row or column. Map all outside clues to their zones immediately. | 高级 |
| Cross-Side Reasoning | If left clue digit X must be in cols 1–3, and right clue digit X is in the same row, that row already places X — the other side confirms its column. | 高级 |
| Box-Side Interaction | An outside clue for a row interacts with the box containing cols 1–3. If the row's box is heavily constrained, the outside digit's position may be forced. | 高级 |
| Digit Elimination from Clues | When a clue digit is placed in the zone, eliminate it from the rest of the zone row/col using standard Sudoku logic. | 高级 |
| Dual-Side Chains | Combine left and right clues for the same row: both digits restrict the same three columns from opposite ends, leaving the middle box fully determined. | 高级 |
平均解题时间
简单
8 分钟
中等
18 分钟
困难
36 分钟
专家
65 分钟
常见问题
什么是外部数独？
Outside Sudoku is a variant where digits appear outside the grid's borders, one or more per row and per column. Each outside digit must appear somewhere within the first three cells of the row or column it points into (the nearest three to that outside clue). Standard Sudoku rules apply throughout.
How far into the grid do outside clues reach?
Each outside clue constrains only the first three cells of its row or column — the three cells nearest to where the clue is placed. A clue on the left side of row 5 means that digit must be in column 1, 2, or 3 of row 5. A clue on the top of column 4 means that digit must be in row 1, 2, or 3 of column 4.
Can an outside digit appear in any of the three cells?
Yes — the clue only guarantees the digit is somewhere in those first three cells, not which one. When multiple outside clues constrain the same three-cell window, their interactions can pin specific cells very precisely. Cross-referencing horizontal and vertical outside clues is the primary solving technique.
Is Outside Sudoku hard to learn?
The rule is simple but the deductions require careful accounting of which digits must appear in which windows. Easy puzzles are accessible for Sudoku players of all levels. Harder puzzles demand systematic tracking of all outside constraints simultaneously across every border.
What is the best first move in Outside Sudoku?
Find rows or columns where outside clues constrain all three cells in the first window. If three different clues each point to the same window, those three cells are fully determined in terms of which digits they contain (though not necessarily in which order). This is the fastest path to early placements.
How long does Outside Sudoku take to solve?
Easy puzzles take 8–18 minutes. Medium puzzles run 18–35 minutes. Hard puzzles average 35–65 minutes and expert puzzles can exceed 90 minutes. The key variable is how many outside clues are provided and how tightly they constrain each three-cell window.