Solution to the weekly extreme Str8ts puzzle #31 from www.str8ts.com

1. Weekly Extreme Str8ts Puzzle#31, January 23 - January 29, 2011www.str8ts.com Solution by SlowThinker

2. Start

3. A4=2c, A3=3s, C4=1c

4. B2=2c, B1=1c, D2=3c, C4=4c

5. D2=2c, H2=6s(FGHJ2)

6. J8=4c, B6=7c

7. J7=3s, B7=6s, B9=8s

8. C3=2h

9. Removingcandidates Compartmentchecks, high/low, strandeddigits (e.g. 1 in G5), naked pair, etc.

10. C8=8s(C789) … andremovingsome additional candidates

11. D5=8s, C5=5c, C1=3s, E1=4s

12. G7=5s

13. H9=4p, H6=1s, H7=2s

14. G6=3c, G8=2s, F8=1s, F9=2c, E9=3s

15. Setti‘srule: C9=6 Setti‘s rule: the number of columns and rows, where a digit appears, must be exactly the same. 6 must appear in every column  6 must appear in row C

16. C9=6S, C7=7c

17. A8=6s, D8=7s, D9=9s, A9=7s

18. D7=5s, A7=9s, D6=6s, E6=5s

19. Y-Wing: G5=4 Y-Wing strategy: attack a candidatefromtwosidesOrange path: E3=7  E5=6  G5:-6  G5=4Blue path: E3=9  G3=7  G1=6  G5:-6  G5=4 Note:becauseofthedetourto G1 thisis not a„pure“ Y-Wing strategy

20. G5=4y, G7=1s

21. F2=9p, F5=7s, E5=6s

22. F4=8c, F1=5s

23. J4=6stranded digit, J1=8s, J3=5s

24. H3=8s, H1=7s, H4=5s

25. G1=6s, G3=7c, E3=9s, E4=7s Done

26. Weekly Extreme Str8ts Puzzle #31www.str8ts.com Solution by SlowThinker Note: There are other (maybe easier or more logical) ways to solve this puzzle.