Kropki數獨
2
1
4
5
7
4
9
8
2
1
7
4
2
7
3
8
4
6
3
1
4
9
8
1
2
3
7
3
5
6
7
4
2
7
6
4
9
1
白點 = 連續數字；黑點 = 一個數字是另一個的兩倍
什麼是 Kropki數獨？
Kropki數獨在相鄰單元格對之間放置點。白點表示兩個數字正好相差1（連續）。黑點表示一個數字正好是另一個數字的兩倍（例如，2和4，或3和6）。如果沒有點出現，則兩個條件都不適用。一些Kropki謎題使用「否定限制」，其中沒有點保證兩個條件都不成立，從而提供更多信息。
一覽
| 約束類型 | 單元格關係 |
| 典型給定數字 | 18–24 |
| 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 | 35 分鐘 |
| 平均解題時間 — 專家 | 62 分鐘 |
如何解 Kropki數獨
| 技巧 | 它的作用 | 等級 |
|---|---|---|
| White Dot Pairs | White dots mark consecutive digit pairs: (1,2), (2,3), …, (8,9). Cross-reference with row and column constraints. | 進階 |
| Black Dot Pairs | Black dots mark double-relationship pairs: (1,2), (2,4), (3,6), (4,8). Only these four combinations are valid. | 進階 |
| Negative Constraint | No dot between two cells means they are neither consecutive nor in a 1:2 ratio — a powerful elimination on every unmarked adjacent pair. | 進階 |
| Dot Chain Analysis | A sequence of connected dots forms a digit-value chain. Enumerate valid digit sequences for the entire chain simultaneously. | 進階 |
| 1-2-4 and 2-4-8 Chains | A black dot adjacent to a white dot often forces the common 1→2→4 or 2→4→8 chain. | 進階 |
平均解題時間
簡單
8 分鐘
中等
18 分鐘
困難
35 分鐘
專家
62 分鐘
常見問題
乜嘢係Kropki Sudoku？
Kropki Sudoku is a variant where dots appear between adjacent cells. A black dot means one of the two cells holds exactly double the value of the other. A white dot means the two cells hold consecutive digits (differing by 1). Standard Sudoku rules apply, and crucially: if there is no dot between two adjacent cells, they are guaranteed NOT to be consecutive and NOT to have a double relationship.
What does a black dot mean?
A black dot between two cells means one digit is exactly twice the other. For example: 1&2, 2&4, 3&6, 4&8. Note that 1&2 satisfies both black (1×2=2) and white (|2-1|=1) conditions — in Kropki Sudoku, a black dot is used when only the doubling relationship holds, not the consecutive one, unless specified otherwise.
What does a white dot mean?
A white dot between two cells means the digits differ by exactly 1: they are consecutive. Valid pairs are 1&2, 2&3, 3&4, 4&5, 5&6, 6&7, 7&8, 8&9. The order doesn't matter — either cell can hold the higher or lower digit.
How does the no-dot constraint work?
In standard Kropki Sudoku, every possible black dot and white dot relationship is marked. This means that if no dot appears between two adjacent cells, you can be certain those cells are neither consecutive nor in a 1:2 ratio. This negative information is just as powerful as the positive dot clues.
Is Kropki Sudoku harder than regular Sudoku?
Easy Kropki puzzles are accessible and make excellent teaching tools for the variant. Hard and expert puzzles are significantly more challenging than classic Sudoku because you must simultaneously track dot relationships and the negative no-dot constraint across every pair of adjacent cells.
How long does Kropki 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 often exceed 90 minutes. Mastering the no-dot constraint is the key to faster solve times at all levels.