クロッキー数独
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
クロッキー数独の遊び方
標準数独ルールが適用されます。隣接する2つのセルの間の黒い点: 一方の数字が他方のちょうど2倍。白い点: 2つの数字は連続（差が1）。点がない場合: どちらの条件も適用されません。
完全ガイド →
白い点 = 連続する数字; 黒い点 = 一方の数字が他方の2倍
クロッキー数独とは？
Kropki Sudokuは隣接するセルのペアの間にドットを配置します。白いドットは2つの数字の差が正確に1（連続）であることを意味します。黒いドットは一方の数字が他方の正確に2倍であることを意味します（例：2と4、または3と6）。ドットがない場合、どちらの条件も適用されません。一部のKropkiパズルは「否定制約」を使用し、ドットがないことでどちらの条件も成立しないことが保証され、さらに多くの情報を提供します。
概要
| 制約タイプ | セルの関係 |
| 典型的な初期数字 | 18–24 |
| 難易度評価 | ★★★☆☆ 3/5 |
| 平均解答時間 — 簡単 | 8分 |
| 平均解答時間 — ミディアム | 18分 |
| 平均解答時間 — 難しい | 35分 |
| 平均解答時間 — エキスパート | 62分 |
クロッキー数独 の解き方
| テクニック | それが何をするか | レベル |
|---|---|---|
| White Dot Pairs | White dots mark consecutive digit pairs: (1,2), (2,3), …, (8,9). Cross-reference with row and column constraints. | 上級 |
| Black Dot Pairs | Black dots mark double-relationship pairs: (1,2), (2,4), (3,6), (4,8). Only these four combinations are valid. | 上級 |
| 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. | 上級 |
| Dot Chain Analysis | A sequence of connected dots forms a digit-value chain. Enumerate valid digit sequences for the entire chain simultaneously. | 上級 |
| 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. | 上級 |
平均解答時間
簡単
8分
ミディアム
18分
難しい
35分
エキスパート
62分
よくある質問
Kropki Sudokuとは何ですか？
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.