? First of all, find a breakthrough and fill in the blanks that can only decide which number to fill in. In this example, there are four steps, and the numbers are filled in blue. As shown in table 1.
? The first step is to fill in 9 in the second column of row F. There are two reasons: 1 column, 1 column, 3 columns all have 9, 2 columns and D columns also have 9. Therefore, for the space that can be filled with 9 in the left middle square, there is only one space in row F and column 2, so fill it in.
? Step 2, fill in 3 in the fifth column of line F. There are two reasons: the sixth column 1, 3, 2, D line and E line 3. Therefore, for the space that can be filled with 3 in the middle square, only F rows and 5 columns are empty, so it is filled.
? Step 3, fill in 6 in the fifth column of row D. There are two reasons: 1, column 4 and column 6 have 6. Therefore, there are five columns of F rows and five columns of D rows in the square right in the middle. And because in the second step, the space in the fifth column of line F has been filled with 3, so this step can only fill in the 6 in the fifth column of line D. (Note, even if it is fixed, it will be handled as fixed before, and it will not be so tired. )
? Step 4, fill in 4 in row 6 of F. Reason: Lines 7, 8 and 9 of 1 f have been filled in. 2. Only 4, 7, 8 and 9 can be filled in the middle box. Therefore, for the middle square F, row 6 and column 6, only 4 can be filled in this blank.
? Secondly, if you find a number, you can only fill in two spaces to find it, and mark it with a fillable number, and the number is filled in black. The method is as above, as shown in Table 2.
? Then, if you find a blank, you can only fill in two numbers, and the numbers are filled in pink; And find other possible numbers in the blank filled with black numbers in Table 2, and fill them in small orange letters. As shown in Table 3.
Finally, use Table 3 for reasoning. F 1, F7 and F8, which are the most difficult to coordinate, restrict each other. There are two situations: 1. F 1 is filled with 2, F7 with 6 and F8 with 5. 2. Fill in 6 for F 1, 5 for F7 and 2 for F8.
? Inference downward, empty reasoning of multiple numbers, inferring that the numbers that can't be filled in are covered by cyan shadow, leaving the correct ones; Infer the correct number to fill in the blanks and fill in the green numbers.
? Assuming that the first situation is satisfied, we infer from Table 4 that B9 and H9 conflict, and all of them are filled with 9, while G8 and B8 conflict, and all of them are filled with 6, which has been marked with yellow shading. Therefore, the original assumption is wrong.
? Assuming that the second case is satisfied, the inference result is shown in Table 5. No contradiction
Note: I originally made it in Word, but I always failed to upload attachments, and then I made drawings and tables with a drawing board, but some of the uploaded pictures were distorted in color, and I don't know why. But that's how the digital Sudoku map is filled out. Take the first stage as an example. I wrote every step in detail and the rest in stages, because the principle is the same. Write every step, and it becomes a paper. If you don't know anything, ask again. Learn to fill in according to my above steps. I'm sure you can just fill in a few. Very good at logical reasoning, come on!