| Easy Puzzle #10 - One Possible Solution Approach | |||||||||||
| NB: There is only one final solution to this Sudoku puzzle | |||||||||||
| Rules: Place a number from 1-9 in each empty cell so that each row, each column AND each 3x3 block contains all the numbers from 1-9. | |||||||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | |||||||||||
| 2 | AA | BB | CC | Reference to 3x3 Blocks AA, BB & CC | |||||||
| 3 | |||||||||||
| 4 | |||||||||||
| 5 | DD | EE | FF | Reference to 3x3 Blocks DD, EE & FF | |||||||
| 6 | |||||||||||
| 7 | |||||||||||
| 8 | GG | HH | II | Reference to 3x3 Blocks GG, HH & II | |||||||
| 9 | |||||||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 3 | Easy Puzzle #10 - October 10, 2005 | |||||||
| 2 | 9 | 4 | 3 | 2 | 7 | Original puzzle as published on joe-ks.com | |||||
| 3 | 2 | 5 | 4 | 9 | |||||||
| 4 | 6 | 8 | 3 | 5 | |||||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | |||||
| 6 | 7 | 8 | 1 | 6 | |||||||
| 7 | 7 | 2 | 8 | 3 | 9 | 1 | |||||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 3 | Step 1: #2 is in Columns A & C: #2 MUST go in Cell B6 | |||||||
| 2 | 9 | 4 | 3 | 2 | 7 | ||||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step 2: #8 is in Columns D & F: #8 MUST go in Cell E3 | |||||
| 4 | 6 | 8 | 3 | 9 | 5 | (cf #8 in Row 1 @ C1 excludes use of Cell E1) | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | |||||
| 6 | 2 | 7 | 8 | 1 | 6 | Step 3: #9 is in Columns G & I: #9 MUST go in Cell H4 | |||||
| 7 | 7 | 2 | 8 | 3 | 9 | 1 | |||||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 3 | Step 4: #8 is in Rows 1 & 3: #8 MUST go in Cell H2 | |||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step #5: #5 is in Rows 8 & 9: #5 MUST go in Cell H7 | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | Step #6: Complete Block DD: need #s 3 & 4 | ||||
| 6 | 3 | 2 | 7 | 8 | 1 | 6 | #3 can't go in Cell C4 (cf #3 in Row 4 @ G4), so | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | #3 MUST go in Cell A6, & therefore #4 MUST go in Cell C4 | |||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 6 | 3 | Step 7: Complete Column H: #6 MUST go in Cell H1 | ||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step 8: Now #6 is in Columns H & I: #6 MUST go in Cell G8 | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | Step 9: Block GG needs #1: #1 can't go in Cells B7 or B9 | ||||
| 6 | 3 | 2 | 7 | 8 | 1 | 6 | (cf #1 in Column B @ B5) nor in Cells A8 or C8 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | (cf #1 1 in Row 8 @ F8): only cell left for #1 is @ A9 | |||
| 8 | 5 | 1 | 6 | 3 | |||||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | |||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 6 | 3 | Step 10: Complete Block FF: need #s 4 & 7 | ||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | #7 can't go in Cell G6 (cf #7 in Row 6 @ C6), so | ||||
| 3 | 2 | 8 | 5 | 4 | 9 | #7 MUST go in Cell G5, & therefore #4 MUST go in Cell G6 | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 11: Complete Block II: need #s 2 & 4 | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | #2 can't go in Cell I9 (cf #2 in Row 9 @ F9), so | |||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | #2 MUST go in Cell I8, & therefore #4 MUST go in Cell I9 | |||
| 8 | 5 | 1 | 6 | 3 | 2 | ||||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | 4 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 12: Complete Block CC: need #s 1 & 5 | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | #1 can't go in Cell G1 (cf #1 in Row 1 @ D1), so | ||||
| 3 | 2 | 8 | 5 | 1 | 4 | 9 | #1 MUST go in Cell G3, & therefore #5 MUST go in Cell G1 | ||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 13: #9 is in Columns A & B: #9 MUST go in Cell C8 | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | 4 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 14: Row #4 needs #1: #1 MUST go in Cell E4 | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | (#1 in Column D @ D1 excludes use of Cell D4, and | ||||
| 3 | 2 | 8 | 5 | 1 | 4 | 9 | #1 in Column F @ F8 excludes use of Cell F4) | ||||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | ||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 15: Row #9 needs #9: #9 MUST go in Cell D9 | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | (cf #9 in Column B @ B2 excludes use of Cell B9) | |||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | |||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 16: Complete Row 9: #3 MUST go in Cell B9 | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 17: #3 is in Rows 1 & 2: #3 MUST go in Cell C3 | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | (cf Step 16's #3 excludes use of Cell B3) | |||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | ||||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 18: Complete Column C: #1 MUST go in Cell C2 | |||||
| 2 | 9 | 1 | 4 | 3 | 2 | 8 | 7 | ||||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 19: #6 is in Rows 8 & 9: #6 MUST go in Cell F7 | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | ||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | ||||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | |||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 20: Complete Row 7: #4 MUST go in Cell B7 | |||||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 3 | 8 | 5 | |||||||