The New Sudoku Players' Forum

[Leren]

Both are easy (at least for a computer). The first puzzle didn't require any diagonal based moves (other than singles). Leren

[m_b_metcalf]

Both are easy (at least for a computer). The first puzzle didn't require any diagonal based moves (other than singles). Leren

Well, all puzzles are easy for a computer. As the subject line indicates, these two are intended for dogged humans.

Mike

[m_b_metcalf]

The first puzzle didn't require any diagonal based moves (other than singles). Leren

Leren,
This one is also easy but heavily dependent on intersections:

Code: Select all

 . . . . . . . . .
 . . . . . . . . 1
 . . 2 . . . . . 3
 . . . . . . . . .
 . . . . . . . . .
 . 4 . 5 . . 6 . .
 . . . 4 . 7 . . .
 . . 3 . . . . . 2
 . . 1 . . . . . 8   

Regards,

Mike

[m_b_metcalf]

Another X-sudoku for the human solver:

Code: Select all

 . . . . . . . 1 2
 . . . . . 3 . . .
 . . 4 . 5 1 . . .
 . . 3 . . . 6 . .
 6 . . . . . . . 1
 . . 2 . . . 7 . .
 . . . 6 8 . 9 . .
 . . . 7 . . . . .
 8 9 . . . . . . .

.......12.....3.....4.51.....3...6..6.......1..2...7.....68.9.....7.....89.......   

Mike

[Leren]

Code: Select all

*----------------------------------------------------*
|d35    35    89   | 49  6   7    | 48  1      2     |
| 79    1     6789 | 49  2   3    | 458 469    45679 |
| 279   267   4    | 8   5   1    | 3   679    679   |
|------------------+--------------+------------------|
| 14579 4578  3    | 2   149 49   | 6   45     4589  |
| 6     45    59   | 3   7   8    | 245 2459   1     |
| 149   48    2    | 5   149 6    | 7   349    3489  |
|------------------+--------------+------------------|
| 23457 23457 1    | 6   8   245  | 9   23457  3457  |
| 245-3 46    56   | 7  a349 2459 | 1   8      3456  |
| 8     9     67   | 1  b34  245  | 245 67    c35    |
*----------------------------------------------------*

Example of a diagonal based "Skyscraper" (3) r8c5 = r9c5 - r9c9 = (3) r1c1 => - 3 r8c1.

<edit> Fixed Typo - Thanks Hajime

Leren

[Hajime]

Example of a diagonal based "Skyscraper" (3)r8c5 = r9c5 - r9c9 = (3) r1c1 => - 3 r9c1.

A Skyscraper or X-chain of length 4 cells requires that r9c1 must 'see' r8c5 and r1c1 both, isn't ?

[Hajime]

Code: Select all

  . . 1 . 9 . 3 . .   
  . . . . 5 . . . .   
  . . . 1 4 6 . . .   
  . . 8 . . . 2 . .   
  2 . . 5 1 9 . . 6   
  . . 9 . . . 5 . .   
  . . . 3 6 1 . . .   
  . . . . 8 . . . .   
  . . 4 . 2 . 7 . .   


After basics:

Code: Select all

+-------------------+------------+--------------------+   
| 4578   24568   1  | 278  9   28|  3   245678   2578 |   
| 4689   24789   26 | 278  5   3 | 16   26789   124789|   
| 3589   23589  2357|  1   4   6 | 89   25789   25789 |   
+-------------------+------------+--------------------+   
| 1357   1357    8  |  6   37  4 |  2    1379    1379 |   
|   2     347    37 |  5   1   9 | 48    3478     6   |   
| 13467  13467   9  | 28   37  28|  5    1347    1347 |   
+-------------------+------------+--------------------+   
| 5789   25789  257 |  3   6   1 | 489  24589   24589 |   
| 1569   23569  256 |  4   8   7 | 16    2359   12359 |   
|  368    168    4  |  9   2   5 |  7    1368     38  |   
+-------------------+------------+--------------------+   


This one needs some more X-chains of length 4, like SkyScraper,Turbot-crane,2-String-Kite and diagonal variants

<edit> maybe indeed 6 of them are too much for a "dogged human solver"
Here is a possible solution path with naked/hidden pairs/triples, pointing&claiming and those 6 X-chains

Hidden Text: Show

Code: Select all

[1,1] r9c4=9 Naked Single
[1,2] r9c6=5 Naked Single
[2,3] r2c6=3 Hidden Single in box 2
[3,3] Naked/Hidden Pairs,Triplets,Quads  | NQuad (3467)b5e1238 [HPair (28)b5e79] => (-467)r6c4 (-47)r6c6 | NQuintet (23478)b5e23789 [HSingle (6)b5e1] => (-47)r4c4 | NQuad (2378)b5e2789 [HPair (46)b5e13] => (-7)r4c6 | NPair (28)r6c46 => (-8)r6c8 (-8)r6c9 | NSingle (4)c6r4 => (-4)r8c6 | NPair (47)c6r48 => (-7)r1c6 | NTriple (489)c7r357 [HPair (16)c7r28] => (-489)r2c7 (-49)r8c7 | NPair (47)r8c46 => (-7)r8c1 (-7)r8c2 (-7)r8c3 (-4)r8c8 (-4)r8c9 | NSingle (7)r8c6 => (-7)r8c4 | NSingle (6)\4 => (-6)r1c1 (-6)r2c2 (-6)r8c8 | NSingle (4)/4 => (-4)r1c9 (-4)r2c8
[4,4] r4c4=6 Naked Single
[4,5] r4c6=4 Naked Single
[4,6] r8c4=4 Naked Single
[4,7] r8c6=7 Naked Single
[5,7] Pointing, Claiming  | (7)\,b1 => (-7)r1c2 (-7)r2c1 (-7)r2c3 (-7)r3c1 (-7)r3c2 | (3)/,b7 => (-3)r8c1 (-3)r8c3 (-3)r9c2
[6,7] 2-String-Kite,SkyScraper,TurbotCrane  |
Turbot Crane (8)r1c6=r6c6-r6c4=r6c6 => (-8)r1c1
[7,7] 2-String-Kite,SkyScraper,TurbotCrane  |
Skyscraper (6)r2c3=r8c3-r8c7=r2c7 => (-6)r2c1 (-6)r2c8
[8,7] Naked/Hidden Pairs,Triplets,Quads  | NQuintet (25789)b3e35789 [HTriple (146)b3e246] => (-2578)r1c8 (-2789)r2c9 | NQuintet (25789)/12367 [HPair (36)/89] => (-259)r8c2 (-8)r9c1
[9,7] Naked/Hidden Pairs,Triplets,Quads  | NPair (36)b7e57 => (-6)r8c1 (-6)r8c3 (-6)r9c2
[10,8] r2c3=6 Hidden Single in col 3
[10,9] r8c7=6 Hidden Single in col 7
[10,10] r1c8=6 Hidden Single in col 8
[10,11] r2c9=4 Hidden Single in box 3
[10,12] r9c1=6 Hidden Single in box 7
[10,13] r8c2=3 Hidden Single in sudokuX/
[11,14] r2c7=1 Naked Single
[12,15] r6c2=6 Hidden Single in row 6
[13,15] Pointing, Claiming  | (9)/,b3 => (-9)r3c8 (-9)r3c9
[14,15] 2-String-Kite,SkyScraper,TurbotCrane  |
Turbot Crane (4)r5c2=r1c2-r1c1=r7c7 => (-4)r5c7
[15,16] r5c7=8 Naked Single
[16,17] r3c7=9 Naked Single
[16,18] r7c7=4 Naked Single
[17,19] r1c2=4 Hidden Single in row 1
[17,20] r5c8=4 Hidden Single in row 5
[17,21] r6c1=4 Hidden Single in row 6
[18,22] r5c2=7 Naked Single
[18,23] r5c3=3 Naked Single
[19,24] r3c1=3 Hidden Single in row 3
[19,25] r9c9=3 Hidden Single in sudokuX\
[20,25] Naked/Hidden Pairs,Triplets,Quads  | NPair (15)r4c12 => (-1)r4c8 (-1)r4c9
[21,25] 2-String-Kite,SkyScraper,TurbotCrane  |
2-String Kite (8)r2c1=r7c1-r9c2=r9c8 => (-8)r2c8
[22,25] 2-String-Kite,SkyScraper,TurbotCrane  |
Turbot Crane (8)r1c6=r6c6-r6c4=r1c9 => (-8)r1c4
[23,25] 2-String-Kite,SkyScraper,TurbotCrane  |
Turbot Crane (8)r2c2=r6c6-r6c4=r2c4 => (-8)r2c1
[24,26] r2c1=9 Naked Single
[25,27] r7c1=8 Hidden Single in col 1
[25,28] r7c2=9 Hidden Single in col 2
[25,29] r7c3=7 Hidden Single in box 7
[25,30] r9c8=8 Hidden Single in box 9
[25,31] r1c1=7 Hidden Single in sudokuX\
[25,32] r8c8=9 Hidden Single in sudokuX\
[25,33] r1c9=5 Hidden Single in sudokuX/
[25,34] r6c4=8 Hidden Single in sudokuX/
[26,35] r1c4=2 Naked Single
[26,36] r1c6=8 Naked Single
[26,37] r2c4=7 Naked Single
[26,38] r2c8=2 Naked Single
[26,39] r3c8=7 Naked Single
[26,40] r3c9=8 Naked Single
[26,41] r4c8=3 Naked Single
[26,42] r6c6=2 Naked Single
[26,43] r6c8=1 Naked Single
[26,44] r6c9=7 Naked Single
[26,45] r7c8=5 Naked Single
[26,46] r7c9=2 Naked Single
[26,47] r8c9=1 Naked Single
[26,48] r9c2=1 Naked Single
[27,49] r2c2=8 Naked Single
[27,50] r3c3=5 Naked Single
[27,51] r4c2=5 Naked Single
[27,52] r4c5=7 Naked Single
[27,53] r4c9=9 Naked Single
[27,54] r6c5=3 Naked Single
[27,55] r8c1=5 Naked Single
[27,56] r8c3=2 Naked Single
[28,57] r3c2=2 Naked Single
[28,58] r4c1=1 Naked Single


[Leren]

Code: Select all

*-------------------------------------------*
| 57    4    1   | 27  9   28 | 3 6    2578 |
| 9-8  *289  6   |*278 5   3  | 1 27   4    |
| 3     258  257 | 1   4   6  | 9 2578 2578 |
|----------------+------------+-------------|
| 15    15   8   | 6   37  4  | 2 379  79   |
| 2     7    3   | 5   1   9  | 8 4    6    |
| 4     6    9   |*28  37 *28 | 5 137  17   |
|----------------+------------+-------------|
| 5789  2589 257 | 3   6   1  | 4 2589 289  |
| 159   3    25  | 4   8   7  | 6 259  1259 |
| 6     18   4   | 9   2   5  | 7 18   3    |
*-------------------------------------------*

Interesting example of a Column/Main Diagonal X Wing.

Leren

[m_b_metcalf]

Here's one wih the clues arranged symmetrically on 3 rows only:

Code: Select all

 . 1 2 3 . 4 5 6 .
 . . . . . . . . .
 . . . . . . . . .
 4 5 7 . 2 . 6 1 8
 . . . . . . . . .
 . . . . . . . . .
 2 . 1 8 6 7 9 . 3
 . . . . . . . . .

..........123.456...................457.2.618..................2.18679.3.........

Mike

[Leren]

Code: Select all

*------------------------------------------------------*
| 3    678  4  | 12567 1789   125689 | 278 789   179   |
| 78   1    2  | 3     789    4      | 5   6     79    |
| 5    678  9  | 1267  178    1268   | 3   478   1247  |
|--------------+---------------------+-----------------|
| 16   29   38 | 467   14578 *18     | 247 3479  24579 |
| 4    5    7  | 9     2      3      | 6   1     8     |
| 16   29   38 | 17    14578 *68     | 247 3479  24579 |
|--------------+---------------------+-----------------|
| 79-8 37-8 5  | 124   1349   129    |*478 2478  6     |
| 2    4    1  | 8     6      7      | 9   5     3     |
|*789  378  6  | 245   349    259    | 1   247-8 47    |
*------------------------------------------------------*

Interesting move, a Double Diagonal Skyscraper : (8) r9c1 = r4c6 - r6c6 = (8) r7c7 => - 8 r7c12, r9c8

Leren