### SB: Single Box

Look at rows and columns. If a numbers only is present in a spesific box we can remove the number from the other rows in the spesific box. Here is a sudoku (which is solved as far as possible with IG, SiSo and SC).

 7 8 2 1 9 4 1 4 9 6 2 7 9 2 4 1 1 4 8 5 7 9 6 5 4 5 4 8 3 5 4 4 1 5 7 2 5 4 6

If you look at the solution table you will see that R9C7 and R9C9 are the only cells in R9 which contains the number 1. This means one of these cells must contain the number 1. Therefore we can remove 1 from B9R8 and B9R7. In this case it means R7C7.

 56 7 36 8 2 1 9 4 356 58 1 4 35 9 6 2 7 358 9 2 368 357 37 4 36 1 3568 1 4 236 239 8 239 5 2369 7 278 38 9 6 137 5 4 23 13 267 36 5 12379 4 2379 8 2369 1369 3 689 2678 1279 17 2789 16 5 4 4 689 1 39 5 389 7 3689 2 278 5 278 4 6 23789 13 389 1389

The same way you can look at boxes.

If you look in B6 you will see that C9 is the only column where the number 1 exist. Therefore 1 must be in B6C9 and we can remove 1 from B3C9 and B9C9, in this case R9C9.

 56 7 36 8 2 1 9 4 356 58 1 4 35 9 6 2 7 358 9 2 368 357 37 4 36 1 3568 1 4 236 239 8 239 5 2369 7 278 38 9 6 137 5 4 23 13 267 36 5 12379 4 2379 8 2369 1369 3 689 2678 1279 17 2789 16 5 4 4 689 1 39 5 389 7 3689 2 278 5 278 4 6 23789 13 389 1389

By continue using SB and SC you will be able to solve this sudoku.