外部數獨
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
如何遊玩外部數獨
標準數獨規則適用。每個顯示在網格外面的數字必須出現在該行或列的前三個格（最近的3x3宮）內。左/右的藍色提示指該行的前/最後三個格；頂/底部的藍色提示指該列的前/最後三個格。
完整指南 →
網格外的數字必須出現在該行或列的前三個單元格中
什麼是 外部數獨？
外部數獨將數字放喺網格嘅邊界。每個外部數字必須出現喺佢指向嘅行或列嘅頭三個單元格（最近嘅宮）其中一個。網格內部冇提供標準給定數字——所有提示都來自邊界。呢個創造咗一種唔尋常嘅數獨形式，初始限制完全來自網格外部。
一覽
| 約束類型 | 外部線索 |
| 典型給定數字 | 28–36 given + 4×9 outside clues |
| 難度評級 | ★★★☆☆ 3/5 |
| 平均解題時間 — 簡單 | 8 分鐘 |
| 平均解題時間 — 中等 | 18 分鐘 |
| 平均解題時間 — 困難 | 36 分鐘 |
| 平均解題時間 — 專家 | 65 分鐘 |
如何解 外部數獨
| 技巧 | 它的作用 | 等級 |
|---|---|---|
| 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. | 進階 |
| 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. | 進階 |
| 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. | 進階 |
| 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. | 進階 |
| 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. | 進階 |
平均解題時間
簡單
8 分鐘
中等
18 分鐘
困難
36 分鐘
專家
65 分鐘
常見問題
乜嘢係Outside Sudoku？
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.