Solve Kakuro
Kakuro is the latest Japanese puzzle craze. If you like Sudoku, or are tired of it, Kakuro is for you! The principle is very simple. Fill each cell in the grid with a single digit such that each row or column has the indicated sum without repeating a digit.
Steps
- Look for rows or columns that can only be made with one combination of digits. You'll still have to somehow determine the correct order, but knowing exactly which digits appear in that row is a great start.
- Triangular numbers: 3 in 2 cells, 6 in 3, 10 in 4, 15 in 5, 21 in 6, 28 in 7, 36 in 8, and 45 in 9.
- Triangular numbers plus one: 4 in 2, 7 in 3, 11 in 4, 16 in 5, 22 in 6, 29 in 7, and 37 in 8.
- 45 minus triangular numbers: 45 in 9, 44 in 8, 42 in 7, 39 in 6, 35 in 5, 30 in 4, 24 in 3, and 17 in 2
- 44 minus triangular numbers: 43 in 8, 41 in 7, 38 in 6, 34 in 5, 29 in 4, 23 in 3, and 16 in 2.
- Look for cells that can only take one digit after considering both their row and column restrictions. For example, suppose a 23 in 3 intersects a 28 in 7. The 23 in 3 can only be 6 + 8 + 9. The 28 in 7 can only be 1 + 2 + 3 + 4 + 5 + 6 + 7. The only digit in common is a 6, so that must be in the intersection.
- Find the maximum and minimum digits that could be in any row or column. The triangular numbers are again critical for this step. For example, there are several ways to get 27 in 4, but none of them can use a 1 or a 2 (since the maximum for the other 3 digits is 7 + 8 + 9 = 24) and all need a 9 (since 5 + 6 + 7 + 8 = 26).
- Compare these restrictions with those in the crossing rows. For example, if the above 27 in 4 crossed a 7 in 3, we could conclude that the cell in the intersection contained a 4. That also implies that the 27 is 4 + 6 + 8 + 9.
- If a row or column must contain a certain digit, look for where in that row or column it could go.
- Continually reevaluate these steps as you discover new information. Although you might not be able to say much about a 20 in 5 initially, once you learn that that row contains a 9, then it looks like a 11 in 4 and therefore must be 20 = 1 + 2 + 3 + 5 + 9.
Tips
- Be aware that some numbers only have one possible solution - a two-digit 16 can only be made with a 9 and a 7; so if it crosses a two-digit 17, the intersecting number MUST be a 9, as the 17 can only be made with a 9 and an 8.
- Subtract when you have one cell left in the row/column.
- Go for the smaller numbers first, then the big numbers.
Warnings
- Loud work spaces make it confusing.
Things You'll Need
- Paper (puzzle)
- Pencil
- Quiet work space
- Know how to add up to at most 45
See Also
Kakuro live to play unique Kakuro puzzles online
