The New Sudoku Players' Forum

[Eioru]

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

When you analysis it, the result is crazy....many"2"

[gurth]

re: interesting puzzle

Eioru,

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 *-----------*
 |...|1..|2..|
 |...|...|...|
 |..3|..4|..5|
 |---+---+---|
 |6..|2..|7..|
 |.7.|...|.3.|
 |..8|..5|..9|
 |---+---+---|
 |1..|7..|6..|
 |.5.|...|.1.|
 |..9|..3|..4|
 *-----------*


Nice puzzle! It foxed me. I found a solution, but not the crazy "2" !

Solution:
(1) SSTS (tricks using the Simple Sudoku Technique Set).

(2) ? 3a9, 3b4, 3h7, 9g8, 5g5 ?? leave no place for 5 in box 2.
So -3a9, 3a5, SSTS.

(3) ? -5e3, singles, ??(=contradiction found) 5e3, SSTS.

(4) ? -1c7, singles, ?? 1c7, singles to END.

Trivalue cell c7 turns out to be a good garnet, needing only singles for contradiction of -1c7 and verification of 1c7 to end.

It looks as if such garnets will frequently be met.

[tarek]

Trivalue cell c7 turns out to be a good garnet

Could you provide a link to the precious stone guidebook gurth ???

tarek

[daj95376]

After SSTS,

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 *--------------------------------------------------------------------*
 | 4589   4689   4567   | 1      35689  6789   | 2      4689   3678   |
 | 24589  24689  12467  | 35689  25689  26789  | 3489   4689   1678   |
 | 2789   12689  3      | 689    2689   4      | 189    6789   5      |
 |----------------------+----------------------+----------------------|
 | 6      349    145    | 2      3489   189    | 7      458    18     |
 | 2459   7      1245   | 4689   4689   1689   | 458    3      26     |
 | 234    124    8      | 346    7      5      | 14     26     9      |
 |----------------------+----------------------+----------------------|
 | 1      2348   24     | 7      24589  289    | 6      2589   238    |
 | 2348   5      2467   | 4689   24689  2689   | 389    1      278    |
 | 278    268    9      | 568    1      3      | 58     2578   4      |
 *--------------------------------------------------------------------*


At this point, setting [r2c4]=6 easily leads to a contradiction in [r1/b13] using just 6s. However, deducing [r2c4]<>6 isn't obvious using just 6s. Here's what I derived. Is there a simpler way, using just 6s, to get this elimination?

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[r9c4]=6                                                    => [r2c4]<>6
[r9c2]=6 => { XY-Wing [r12c39] | ( [r5c9]=6 => [r6c4]=6 ) } => [r2c4]<>6


[ronk]

Here's what I derived. Is there a simpler way, using just 6s, to get this elimination?

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[r9c4]=6                                                    => [r2c4]<>6
[r9c2]=6 => { XY-Wing [r12c39] | ( [r5c9]=6 => [r6c4]=6 ) } => [r2c4]<>6


I don't know about simpler, but here's a slightly different view ...

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  .  6 *6  |  .  6  6  |  .  6 *6 
  .  6 *6  | -6  6  6  |  .  6 *6 
  .  6  .  |  6  6  .  |  .  6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  .  |  6  6  6  |  .  . #6 
  .  .  .  |  6  .  .  |  .  6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  . #6  |  6  6  6  |  .  .  . 
  .  6  .  |  6  .  .  |  .  .  . 

If both r5c9<>6 and r8c3<>6, then your r12c39 x-wing implies r2c4<>6
If r5c9=6, the empty rectangle in b5 implies r2c4<>6
If r8c3=6, the empty rectangle in b8 implies r2c4<>6
For all three possibilities, r2c4<>6

I won't try to write an expression.

[RW]

I'm not a fisherman, but isn't this a finned Jellyfish?

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  .  6 *6  |  . *6 *6  |  .  6 *6 
  .  6 *6  | -6 *6 *6  |  .  6 *6 
  .  6  .  |  6 #6  .  |  .  6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  .  |  6 *6 *6  |  .  . *6 
  .  .  .  |  6  .  .  |  .  6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  . *6  |  6 *6 *6  |  .  .  . 
  .  6  .  |  6  .  .  |  .  .  . 

and it's finned Swordfish counterpart:

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  .  6  6  |  .  6  6  |  .  6  6 
  .  6  6  | -6  6  6  |  .  6  6 
  . *6  .  | *6 #6  .  |  . *6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  .  |  6  6  6  |  .  .  6 
  .  .  .  | *6  .  .  |  . *6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  6  |  6  6  6  |  .  .  . 
  . *6  .  | *6  .  .  |  .  .  . 

RW

[ronk]

RW, you're now a fisherman!

[tarek]

and it's finned Swordfish counterpart:

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  .  6  6  |  .  6  6  |  .  6  6 
  .  6  6  | -6  6  6  |  .  6  6 
  . *6  .  | *6 #6  .  |  . *6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  .  |  6  6  6  |  .  .  6 
  .  .  .  | *6  .  .  |  . *6  . 
 ----------+-----------+----------
  .  .  .  |  .  .  .  |  .  .  . 
  .  .  6  |  6  6  6  |  .  .  . 
  . *6  .  | *6  .  .  |  .  .  . 

Nice. I guess this is a bit tricky to spot without pencilmarks

tarek

[daj95376]

Thanks ronk and RW !!! Too bad the remainder of the solution isn't this interesting.

[gurth]

re: Precious Stones Guidebook

Tarek,
I have opened a topic "PEARLS, RUBIES, GARNETS, EMERALDS, ETC." giving definitions of these terms, for which I am responsible.

DIAMONDS are not my province, but rather udosuk's I think. Refer to him regarding diamonds, please.

udosuk,
and anyone else, please feel free to use the new topic to add your own jewelry definitions. Then everything will stay together for ready reference.

For that matter, why confine yourself to gemstones? Anything goes! Maybe flowers... Or else proper names such as "Mona Lisa" ?

[RW]

Nice. I guess this is a bit tricky to spot without pencilmarks

It's tricky to see it's a finned swordfish, but as a Nishio elimination it's not very hard to find (assuming r2c4=6, you can't place the rest of the 6s). But I must admit that in this case I never even looked at the puzzle, only ronks diagram of 6s.

RW