專家 外部數獨
網格外部的線索給出該行或列中遇到的前三個數字 — 但不包括它們的順序。
專家 外部數獨。網站上最難的謎題——每個放置都來自跨邊界和宮約束的精確邏輯推理。無需猜測。
2
3
9
3
4
1
9
7
4
9
2
6
5
3
9
9
3
6
7
9
6
3
2
5
8
8
7
7
3
1
2
8
1
5
4
2
3
1
9
7
8
6
8
7
6
4
3
6
9
5
8
6
7
4
3
7
2
3
5
什麼是 外部數獨？
難度
★★★☆☆
3/5
約束類型
外部線索
典型給定數字
28–36 given + 4×9 outside clues
平均解題（專家）
65 分鐘
解謎技巧（專家 等級）
| 技巧 | 描述 | 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. | 初學者 |
| 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. | 中級 |
| 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. | 中級 |
| 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. | 中級 |
| 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 |
在 專家 需要掌握的技巧
- X翼技巧 — Expert outside grids under-clue the borders, so window logic alone stalls — fish on digits that appear in many clues, since their global positions are the most constrained.
- Swordfish technique — Three rows whose windows trap the same digit in matching columns set up a Swordfish — the standard escape from an expert outside-clue deadlock.
按難度劃分的平均解題時間
簡單
8 分鐘
中等
18 分鐘
困難
36 分鐘
專家
65 分鐘
想要規則、策略和解題步驟的完整解說？
如何遊玩 外部數獨 →
相關變體
Skyscraper數獨
The next step in border-clue logic — outside numbers become visibility counts that constrain entire row orderings.
Sandwich數獨
Border clues with arithmetic teeth: each one is the sum of the digits trapped between 1 and 9.
殺手數獨
Moves the clue layer inside the grid as summed cages — a natural graduation from window placement to sum deduction.
常見問題 — 專家 外部數獨
更多問題？請參閱完整 外部數獨指南.