Strategies for Number Puzzles of all kinds
Caution!
Print Version
Solvers
Puzzles
Latest Apps
Str8ts
Other


Valid XHTML 4.01 Transitional


Discussion...


Post an idea here...
Your Name or Handle

Your comment, idea or question

Please enter the
letters you see:
arrow
Enter these letters
Remember me


Please keep your comments relevant to this puzzle.
Email addresses are never displayed, but they are required to confirm your comments. To state your solve time use the smaller form at the top right of this page." & vbNewLine & _ Line breaks and paragraphs are automatically converted ? no need to use <p> or <br> tags.

Tuesday 6-Dec-2016

... by: ttiah

123456789
457189236
689732541
241378695
835691427
976524318
314967852
568213974
792845163

You have to guess, but then the extreme solvers, while logical, are no more logical than a guess. The negative non-solution must be found to prove the solution. One form of guessing I used was to look at all the solution possibilities for a number, then using your solution count calculator to verify which possibility is a solution. The easiest was 1 since the number of possible solutions is minimum. Very tedious work, and I plan to never do this again, since I would like sudoku to be relaxing.

Tuesday 6-Dec-2016

... by: cenoman

wobien

You misplaced the 5 in box 7: H1=5 in Andrew's puzzle (instead of J1=5 in all your grids).

Monday 5-Dec-2016

... by: wobien

Sorry, another try.
----------------------------
| 1 2 - | 6 9 4 | 7 8 - |
| 4 9 7 | 3 8 5 | 1 2 6 |
| - - - | 3 8 5 | 9 4 - |
----------------------------
| 2 5 1 | 4 7 9 | 6 3 8 |
| 7 3 6 | 8 2 1 | 5 9 4 |
| 9 - - | 5 3 6 | 2 1 7 |
----------------------------
| 3 1 - | 9 6 7 | - 5 2 |
| - - 9 | 2 5 3 | - 7 1 |
| 5 7 2 | 1 4 8 | 3 6 9 |
----------------------------

and also:

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


Monday 5-Dec-2016

... by: Wobien

All my spaces have gone! I post the solutions again with a dash on the empty places.
----------------------------
| 1 2 - | 6 9 4 | 7 8 - |
| 4 9 7 | 3 8 5 | 1 2 6 |
| - - - | 3 8 5 | 9 4 - |
----------------------------
| 2 5 1 | 4 7 9 | 6 3 8 |
| 7 3 6 | 8 2 1 | 5 9 4 |
| 9 - - | 5 3 6 | 2 1 7 |
----------------------------
| 3 1 - | 9 6 7 | - 5 2 |
| - - 9 | 2 5 3 | - 7 1 |
| 5 7 2 | 1 4 8 | 3 6 9 |
----------------------------

and also:

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


Monday 5-Dec-2016

... by: wobien

I don't think this is a valid sudoku. Its solution is not unique. For instance:
----------------------------
| 1 2 | 6 9 4 | 7 8 |
| 4 9 7 | 3 8 5 | 1 2 6 |
| | 3 8 5 | 9 4 |
----------------------------
| 2 5 1 | 4 7 9 | 6 3 8 |
| 7 3 6 | 8 2 1 | 5 9 4 |
| 9 | 5 3 6 | 2 1 7 |
----------------------------
| 3 1 | 9 6 7 | 5 2 |
| 9 | 2 5 3 | 7 1 |
| 5 7 2 | 1 4 8 | 3 6 9 |
----------------------------

and also:

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

can be completed in several ways.

Sunday 4-Dec-2016

... by: Hal

It tells me I have the wrong code. Why?

Sunday 4-Dec-2016

... by: hal

what is wrong?

Saturday 3-Dec-2016

... by: JC Van Hay

0. D3=1; XWing(1RowsBJ)-1H7

Analysis of the puzzle from (1359)AC9 and (7359)GH8 having some of the properties of a Double Exocet on the digits 3, 5, and 9 :

1. 9H8 -> J2=9, XWing{9RowsBD} -> -{9AC9, 9E7}
1a. + 3G8 -> 0 solution via HP(13-2459)B47=9B6
1b. + 5G8 -> 0 solution via XWings{5RowsBD} -> AC9=31
1c. + 7G8 + 1C9 -> 0 solution via XWings{3RowsBJ} -> A9=5
1d. + 7G8 - 1C9 -> 0 solution via NP(35)AC9 -> B8=2
Conclusion, H8=7

2. G8=3 -> J1=3, XWing{3RowsBD}-> -{3AC9, 3F7}
2a. + 1C9 + 5A9 -> 0 solution via XWing{9RowsBD} -> B8=9
2b. + 1C9 + 9A9 -> 0 solution
2c. - 1C9 -> 0 solution via NP(59)AC9 and [(9=5)B5-5D2=5E3-(5=9)E8-9E5=9E6]-(9=5)B6
Conclusion : G8=J6=5, G5=6, NP(29)E58, XWing(5RowsBD) -> -{5AC9, 5E7}, XWing{6Col14} -> -{6C6}

3. -1C9 -> 0 solution via NP(39)AC9 -> B8=2; C9=B4=H5=J6=1, H4=2

4. "SSTS" to a unique solution :
XWing(3RowsBJ)-(3=9)A9; 14 Singles
Pointing{4Box2} -> XWing{4Col39} -> -{4H2}
Jellyfish{8RowsCDEG} -> -{8H2, 8J1}; H2=6
HP(36-28)A3C1
XYWing(367)C14.J1-(7=8)J4; stte

Saturday 3-Dec-2016

... by: ray

1. Use only basic strategies and the forcing bi-location set method.Start with E1{24678}- bi-location cell for 7,tri-location cell for 6 and 7.Progressive
ly form the 3-element bi-location cell set E1D26,forcing only the 1-cell to
3-cells run out values until E1D26 = (8,4,8) which gives the solution.Other
bi-location cell set solutions found were: C6D2F9 = (2,4,8). N.B: using basic to extreme strategies,B7 =2 gave a 1-cell solution.
2. Using this solution,with basic strategies, the following non bi-location cell
solutions: DFJ9 = (5,8,3), D69F9 = (8,5,8), G1H35 = (3,8,1). N.B: using basic to extreme strategies, G1 = 3, D9 = 5, J9 = 3, A9 = 9(Exocet value)
gave 1-cell solutions.

Saturday 3-Dec-2016

... by: anybody1

1 cell sol: 3C5 2C6 8E1 3J9...

Archive

Each week a new 'unsolvable' will be published and the previous will be accessible here from this archive section. If you like very tough puzzles, these are for you.
Share and Enjoy



Post a Comment using Facebook...

Page created on 03-May-2011, last modified on 03-May-2011.
All puzzles on this site are trademarked and copyright
and cannot be reproduced without permission.
Copyright Syndicated Puzzles Inc, 2011-2015