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。每個顯示在網格外的數字必須出現在該行或列的前三個儲存格中（最近的3x3宮）。左/右的藍色提示指該行的前/後三個儲存格；上/下的藍色提示指該列的前/後三個儲存格。
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？
Outside Sudoku 將數字放置在網格的邊緣。每個外部數字必須出現在它指向的行或列的前三個單元格（最近的宮）之一。網格內部不提供標準的給定數字——所有提示都來自邊緣。這創造了一種不尋常的數獨形式，其中初始約束完全來自網格外部。
一覽
| 約束類型 | 外部線索 |
| 典型給定數 | 28–36 given + 4×9 outside clues |
| 難度評分 | ★★★☆☆ 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
什麼是 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.