The New Sudoku Players' Forum

[m_b_metcalf]

This puzzle seems to have some special properties that might challenge human solvers (or even drive them to distraction).

Code: Select all

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

Regards,

Mike Metcalf

[m_b_metcalf]

Code: Select all

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

Nobody seemed to appreciate the first puzzle, maybe this one is more amenable.

Regards,

Mike Metcalf

[David P Bird]

Seeing that no one had risen to the challenge, I had a go at the first one. It took me back the Eureka challenge days!

1.2..34.5.........6..1.2..7..8...2.3.........5.6...8..7..6.1..4.........3.45..7.96..8.49......6.....1.....8.

Code: Select all

 *--------------------------*--------------------------*--------------------------*
 | <1>     789     <2>      | 789     6789    <3>      | <4>     689     <5>      |
 | 489     34579   3579     | 479     45679   45679    | 16      12369   28       |
 | <6>     34589   359      | <1>     4589    <2>      | 39      389     <7>      |
 *--------------------------*--------------------------*--------------------------*
 | 49      1479    <8>      | 479     145679  45679    | <2>     4579    <3>      |
 | 249     123479  1379     | 234789  1345789 4579     | 59      4579    6        |
 | <5>     23479   <6>      | 23479   3479    479      | <8>     479     1        |
 *--------------------------*--------------------------*--------------------------*
 | <7>     28      59       | <6>     39      <1>      | 35      28      <4>      |
 | 289     12569   159      | 3479    3479    479      | 16      35      28       |
 | <3>     16      <4>      | <5>     2       8        | <7>     16      <9>      |
 *--------------------------*--------------------------*--------------------------*

After basics (including (8)fish:c19r28)

01: (9=3)r3c7 - (3=5)r7c7 - (5=9)r9c3 => r3c3 <> 9
02: (3)r2c8 = (3)r3c78 - (3=5)r3c3 - (5)r78c3 = (5-6)r8c2 = (6)r8c7 - (6=1)r2c7 => r2c8 <> 1
. . . &so r2c7,r9c8 = 1, r8c7,r9c2 = 6
03: (5=3)r3c3 - (3)r3c7 = (3-5)r7c7 = (5)r7c3 => r28c3 <> 5
04: (3=5)r3c3 - (5)r7c3 = (5-3)r7c7 = (3)r3c7 => r3c28 <> 3
05: (5)r5c7 = (5-3)r7c7 = (3)r7c5 - (3)r8c4 = (23-8)r56c4 = (8)r5c5 => r5c5 <> 5
06: (6)r4c6 = (6-1)r4c5 = (1-8)r5c5 = (28-3)r56c4 = (3)r8c4 - (3)r7c5 = (3-5)r7c7 = (5)r5c7 - (5=479)r4c148 => r4c6 <> 479
07: (56)r4c56 = (5)r5c6 - (5)r5c7 = (5-3)r7c7 = (3)r8c5 - (3)r8c4 = (23-8)r5c6c4 = (8-1)r5c5 = (1)r4c5 => r4c5 <> 479
08: (1)r5c5 = (1-56)r4c56 = (5)r5c8 - (5=3)r8c8 - (3)r8c4 = (23-8) = (8)r5c5 - Loop
. . . => r5c8 <> 5, r8c5 <> 3, r56c4 <> 479, r5c5 <> 3479
09: (8=9)r3c8 - (9=3)r3c7 - (3)r7c7 = (3)r7c5 - (3)r8c4 = (23-8)r56c4 = (8)r4c5 => r3c5 <> 8
. . . (8)box/Line:r1c45 => r1c28 <> 8
10: (9)r3c8 = (9-3)r3c7 = (3)r7c7 – (3)r7c5 = (3)r8c4 – (23=8)r56c4 – (8=1)r5c5 – (16=5)r4c56 - (5=479)r1c8 <> 9
. . . &so r1c9 = 6, (9)box/line:r3b3 => r3c25 <> 9
11: (5)r3c3 = (5)r7c3 - (5)r7c7 = (5)r5c7 - (5)r4c8 = (56)r4c56 -[DP]- (56)r2c56 = (5)r2c2 => r3c2 <> 5
12: (5)r4c8 = (5)r8c8 - (5)r8c2 = (5)r7c3 - (5)r3c3 = (5)r3c5 => r4c5 <> 5
. . . &so (5)box/line:b5c6 => r2c6 <> 5
13: (5)r2c5 = (5)r3c5 – (5)r3c3 = (5)r7c3 – (5)r8c2 = (5-9)r7c3 = (9-3)r7c5 = (3)r8c4 – (23=8)r56c4 – (8=1)r5c5 – (1=6)r4c5
. . . => r2c5 <> 6
Basics to the end

The chains were found manually aided by the GEM colouring system. I've pruned out some that turned out to be redundant.
Sorry if there are any typos.

DPB

[Marty R.]

This is the simpler one.

Code: Select all

+-------------+----------------------+---------------+
| 1  789  2   | 89    689      3     | 4   679    5  |
| 58 3    479 | 2489  245689   25689 | 167 12679  29 |
| 6  459  49  | 1     2459     7     | 3   29     8  |
+-------------+----------------------+---------------+
| 4  169  8   | 39    13569    1569  | 2   135    7  |
| 2  1679 679 | 34789 13456789 15689 | 15  135    46 |
| 3  167  5   | 247   12467    126   | 9   8      46 |
+-------------+----------------------+---------------+
| 9  258  3   | 6     78       4     | 57  257    1  |
| 58 258  46  | 378   1378     18    | 567 245679 29 |
| 7  46   1   | 5     29       29    | 8   46     3  |
+-------------+----------------------+---------------+


Play this puzzle online at the Daily Sudoku site

9r8c9=(9-4)r8c8=4r8c3-(4=9)r3c3-r2c3=r2c456=>r2c9<>9

[Marty R.]

Basics to the end

David, is that a typo or are you part of the apparently extremely tiny minority who doesn't distinguish between lcstte and stte?

[ArkieTech]

9r8c9=(9-4)r8c8=4r8c3-(4=9)r3c3-r2c3=r2c456=>r2c9<>9

nice one

[David P Bird]

Basics to the end

David, is that a typo or are you part of the apparently extremely tiny minority who doesn't distinguish between lcstte and stte?

Marty, I rather think the minority of the 3983 members of this site are those who know what lcstte stands for.

FYI my basic methods are: 1) Naked and hidden tuples of any size, 2) Box/line eliminations, & 3) Simple Fish.

In line with so many others in this puzzles section, I'm asserting my rights to freedom of choice about what methods I use and how I notate them and will resist any attempts to get me to conform.

Power to the People

[JC Van Hay]

After "Basics" ...

Puzzle 1 : r5c5=8->contradiction :=> r5c4=8; ste via HP(56)B5.
Puzzle 2 : r3c3=9->contradiction :=> r3c3=4; ste

[David P Bird]

This is the simpler one.

Code: Select all

+-------------+----------------------+---------------+
| 1  789  2   | 89    689      3     | 4   679    5  |
| 58 3    479 | 2489  245689   25689 | 167 12679  29 |
| 6  459  49  | 1     2459     7     | 3   29     8  |
+-------------+----------------------+---------------+
| 4  169  8   | 39    13569    1569  | 2   135    7  |
| 2  1679 679 | 34789 13456789 15689 | 15  135    46 |
| 3  167  5   | 247   12467    126   | 9   8      46 |
+-------------+----------------------+---------------+
| 9  258  3   | 6     78       4     | 57  257    1  |
| 58 258  46  | 378   1378     18    | 567 245679 29 |
| 7  46   1   | 5     29       29    | 8   46     3  |
+-------------+----------------------+---------------+


Play this puzzle online at the Daily Sudoku site

9r8c9=(9-4)r8c8=4r8c3-(4=9)r3c3-r2c3=r2c456=>r2c9<>9

Marty, how is the red link strong?

DPB

[Marty R.]

This is the simpler one.

Code: Select all

+-------------+----------------------+---------------+
| 1  789  2   | 89    689      3     | 4   679    5  |
| 58 3    479 | 2489  245689   25689 | 167 12679  29 |
| 6  459  49  | 1     2459     7     | 3   29     8  |
+-------------+----------------------+---------------+
| 4  169  8   | 39    13569    1569  | 2   135    7  |
| 2  1679 679 | 34789 13456789 15689 | 15  135    46 |
| 3  167  5   | 247   12467    126   | 9   8      46 |
+-------------+----------------------+---------------+
| 9  258  3   | 6     78       4     | 57  257    1  |
| 58 258  46  | 378   1378     18    | 567 245679 29 |
| 7  46   1   | 5     29       29    | 8   46     3  |
+-------------+----------------------+---------------+


Play this puzzle online at the Daily Sudoku site

9r8c9=(9-4)r8c8=4r8c3-(4=9)r3c3-r2c3=r2c456=>r2c9<>9

Marty, how is the red link strong?

DPB

David,

How diplomatic of you to ask rather than just state outright that I screwed up.

Even though I don't have a deep understanding of strong and weak inferences, I can easily see that this one isn't strong, even if I took care of the 29 pair in box 3. Thanks for bringing it to my attention; that's how I learn.