I consider all puzzles on this page to be Level 6. But none of these REQUIRE the use of chains. They can all be solved with "coloring" techniques.
To focus on "coloring" techniques, start out with the SECOND showing of each puzzle.
PB Post 2013 02 09 (Repeated lower down)
PB Post 2013 02 09 Same as above, except the green boxes are filled
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First notice the lonely 6/7 pairs in the bottom row, allowing elimination of 6 from E9 and I9.
Then, use colors for 7. FINIS! |
PB Post 2013 02 16 (Repeated lower down)
PB Post 2013 02 16 Same as above, except the pink boxes are filled
To proceed, color the 1's. It becomes evident that D3, then E3 cannot = 1. All the 1's are soon solved. FINIS.
PB Post 2013 04 20 Lvl 6 (Repeated lower down)
PB Post 2013 04 20 Lvl 6 w 33 Same as above, except the pink boxes are filled.
Note: Using "simple" methods, the 7 underlined numbers (A4&5, D3, E9, F2&8) can be eliminated as choices.
To proceed, I used MULTI-COLORING with 4s. It proved that F8 cannot equal 9. FINIS.
PB Post 2013 04 27 Lvl 6 (Repeated lower down)
PB Post 2013 04 27 Lvl 6 w17 Same as above, except the green boxes are filled in.
Note: Using "simple" methods, the underlined 4 in I3 can be eliminated as a choice.
To proceed, I used "color" with 5's. If you mark A1 as being a 5, you will eventually be forced to mark B2 as a 5 also. (You also get two 5's in row 3). Of course, that is WRONG and you end up concluding NEITHER ONE can equal 5; B3 = 5. All the 5's are revealed.
ONE of the several rules of coloring is that ... if you end up with TWO check marks or with TWO X's in the same row, column, or group, then in fact they MUST both be X's! And their opposites MUST be check marks, whose values are now confirmed.
PB Post 2013 05 04 Lvl 6 (Repeated lower down)
PB Post 2013 05 04 Lvl 6 w21 Same as above, except the gray boxes are filled in.
To proceed, I colored 2s. This easily proved that E3 and F2 cannot have a 2.
Simple methods (In row 2, two pairs of 2/6) proved that E2 cannot be an 8, so F2 must equal 8. FINIS
* * * * * * * * * * * * * * * * * * * * * * * *
PB Post 2013 06 15 Lvl 6 (Repeated lower down)
Wonderful puzzle. You think you're almost there, but with only 15 empty boxes, simple techniques fail.
PB Post 2013 06 15 Lvl 6 w15 Same as above, except the blue boxes are filled
With only 15 empty boxes, the easiest way for some people is by coloring 9's. IF you begin by assuming G5 is 9, you run into conflicts which in fact reveals the correct position for the 4 remaining 9s. Even if you assumed G5 was NOT 9, you should be conscious to the fact that it could not be otherwise, because you end up with two NON-9's in a single column and in a single row. Obviously, that could NOT be reversed.
An ALTERNATE solution is to begin a chain with the 7 in E5. Then go on to E8, I8, I2, and finally I6. This proves that D6 cannot be 9, and so D6 = 8. (Other ways exist to get from E5 to D6)
PB Post 2014 04 12 Lvl 6 (Repeated lower down)
PB Post 2014 04 12 Lvl 6 w31 Same as above, except the grayboxes are filled in.
Note: Using "simple" methods, the underlined numbers can be removed as choices.
To proceed, I used "coloring" of 4's, beginning at B1. Even though "multi-coloring" might be applied, the single coloring was sufficient to reveal FOUR DIFFERENT boxes that must contain 4!!
Pretty easy to finish after that.
PB Post 2014 04 26 Lvl 6 (Repeated lower down)
Kickoff: You can do all the 3s and all the 7's!
After filling in the pinks, simpler methods fail. Here's results:
PB Post 2014 04 26 Lvl 6 w27 Same as above, except the pink boxes are filled in.
I was able to solve by coloring 8's. I ASSUMED that F1 = 8. This eventually led to a conflict, proving - in fact - that G1 = 8. Three other 8's were also determined.
FINIS
I never tried chains, but did try the "GUESS" method with doubles. Find it on the GUESS method page.
PB Post 2014 05 03 Lvl 6 (Repeated lower down)
To focus on "coloring" techniques, start out with the SECOND showing of this puzzle.
Here is an account of the order that I followed in solving. Users may have a different experience.
1. There were 6 naked singles.
2. Two hidden 1's, then a hidden 5.
3. In Column A, I used single-line elimination to cross out some 5s.
4. In Column E, single-line eliminations got rid of some 9s.
5. In Column F, 4/7 doubles allowed me to make several eliminations and prove that F1 = 8
6. Found a hidden 8
7. In Column D, 3/4 doubles means D4 is not 4; D4 = 5
8. In Column E, single-line eliminations of 4s in groups 2 & 8.
FINALLY - with 39, simple techniques failed me. See next puzzle:
PB Post 2014 05 03 Lvl 6 w39 Same as above, except the green boxes are filled in.
Note: Using "simple" methods, the 10 underlined numbers can be eliminated as choices.
To proceed, I colored 4's, beginning with B1. This PROVED that B1 and other could NOT equal 4; it revealed four boxes that MUST equal 4.
The rest were naked singles!
An alternate solution of this puzzle exists: Guessing that A2 = 4 leads to a clash, proving that A2 must equal 3.
PB Post 2014 06 07 Lvl 6 (Repeated lower down)
Remarkable puzzle because stuck for advanced methods with only 16 remaining.
PB Post 2014 Lvl 6 w 16 Same as above, except the pink boxes are filled in.
Note: Using "simple" methods, the 2 underlined 8s can be removed as choices. In both cases, single-line elimination along a row or column was adequate. Solution (next sentence) may not even require their removal this way.
To proceed, I colored 9s, beginning at A3. You end up proving that A3 CANNOT be a 9, and all four remaining 9s are revealed. The puzzle is soon solved.
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