The New Sudoku Players' Forum

[999_Springs]

Code: Select all

...|41.|.5.
3..|..8|..1
...|5..|89.
---+---+---
5.7|...|.3.
.3.|...|.2.
.1.|...|4.9
---+---+---
.93|..1|...
2..|9..|..6
.5.|.76|...

I solved this using a grand total of 6 locked candidates type 1, 4 hidden pairs, 3 x-wings, 3 xy-wings, 2 turbot fish, 1 locked candidate type 2, 1 naked pair, 1 grouped turbot fish and 1 y-wing. I think that there may be a somewhat simpler solution. What is it?

(For those who don't already know, I don't use URs.)

[Mike Barker]

Here's a slightly different solution (computer generated) using naked triples (which I didn't see on your list) and an empty rectangle (which may be your grouped Turbot Fish) for a total of 4 locked candidates, 1 naked pair, 3 naked triples, 1 ER, a finned and a basic X-wing, and 3 XY-wings.

Locked Column Line/Box: r45c7 => r8c7<>1
Locked Row Line/Box: r5c79 => r5c56<>5
Naked Row Triple: r9c138 => r9c4<>8,r9c9<>4
Empty Column Rectangle: r14c3|r1c7 => r4c7<>6
Naked Row Triple: r8c567 => r8c38<>4
Locked Row Line/Box: r9c13 => r9c8<>4
Locked Row Line/Box: r7c89 => r7c5<>4
Column Finned X-Wing: r246c4|r26c8 => r6c5<>6
Row X-Wing: r15c37 => r36c3<>6,r2c7<>6
XY-wing => r6c4<>3,r8c5<>3
Naked Row Pair: r6c48 => r6c6<>7
Naked Column Triple: r389c3 => r5c3<>4
XY-wing => r1c6<>7
XY-wing => r1c7<>2

[tarek]

That r4c7<>6 elimination seems to be an important step, did anyone spot a fish equiv.

tarek

[ronk]

That r4c7<>6 elimination seems to be an important step, did anyone spot a fish equiv.

The "Empty Column Rectangle: r14c3|r1c7" description & notation used by SE is more interesting than the fish.

Code: Select all

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

 r1b4\r4c3 plus fin r1c7

[daj95376]

Although wapati often generates puzzles that need URs, this puzzle doesn't need them. To my knowledge, wapati loves finned/Sashimi fish, turbot fish, and ERs; so I suspect that he might have leaned towards this solution. It's not much different than those proposed earlier. (Note: I group common technique results into a single step, so multiple Locked Candidate 1's may not be necessary.)

Code: Select all

 r9      Naked  Triple                   <> 148  [r9c49]
   c7b6  Locked Candidate 1              <> 1    [r8c7]
 r5  b6  Locked Candidate 1              <> 5    [r5c56]
         XY-Wing  [r5c1]/[r1c1]+[r5c6]   <> 7    [r1c6]
   c48   X-Wing (finned)                 <> 6    [r6c5]
 r247    Swordfish (finned)              <> 4    [r8c8],[r9c8]
   c8b9  Locked Pair                     <> 18   [r7c8]
 r7  b9  Locked Candidate 1              <> 4    [r7c5]
 r8  b8  Locked Candidate 1              <> 4    [r8c3]
 r8      Naked  Pair                     <> 18   [r8c5]
         (2-String Kite)                 <> 6    [r6c3]
   c6b2  Locked Candidate 2              <> 2    [r2c4],[r3c5]
         (Empty Rectangle)               <> 6    [r4c7]
 r15     X-Wing                          <> 6    [r2c7],[r3c3]
   c3    Naked  Triple                   <> 148  [r5c3]
         XY-Wing  [r7c5]/[r6c5]+[r9c4]   <> 3    [r6c4],[r8c5]
 r6      Naked  Pair                     <> 67   [r6c6]
   c48   X-Wing                          <> 6    [r2c2] -or-
 r34     X-Wing                          <> 6    [r2c2]
         XY-Wing  [r1c9]/[r1c6]+[r2c7]   <> 2    [r1c7]


[tarek]

That r4c7<>6 elimination seems to be an important step, did anyone spot a fish equiv.

The "Empty Column Rectangle: r14c3|r1c7" description & notation used by SE is more interesting than the fish.

Code: Select all

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

 r1b4\r4c3 plus fin r1c7

I couldn't spot this finned mutant x-wing. maybe because I THOUGHT r56c3 are not covered (but they are )

tarek

[achievecn]

thanks a lot! Happy new year!