The New Sudoku Players' Forum

[Bernard Stay]

It's a long time since I've had to do this but this is as far as I can get with today's Times 1258 (Super Fiendish). Sudoku Susser can't do it and even declares it erroneous!

12*|3*7|*5*
6**|**5|**3
*5*|1**|***
----------------
9*5|**1|*36
***|6**|***
86*|5**|9*7
----------------
*86|**4|***
5**|8**|**2
*1*|7*6|*48

I have reduced C9 to 4/9 4/9 1/5 1/5 and box 5 to 2/4, 7/8,
7/8/9, 8/9, 2/3/4, 2/3 and confined 3 to R2 of box 4 and to R3 of box 5 but that's about it.

Hints? Thanks.

[udosuk]

Sudoku Susser couldn't do it because you've made a mistake...

r7c23 cannot have been [86]... I suggest you clear those 2 cells (and all pencilmarks), and start again...

(The grid you posted doesn't have a valid solution...)

Having no access to the original puzzle, I can only guess it's:

Code: Select all

 *-----------*
 |12.|3.7|.5.|
 |6..|..5|..3|
 |...|1..|...|
 |---+---+---|
 |9.5|..1|.36|
 |...|...|...|
 |86.|5..|9.7|
 |---+---+---|
 |...|..4|...|
 |5..|8..|..2|
 |.1.|7.6|.48|
 *-----------*

... from symmetricalising the grid you posted... There could have been even fewer clues...

PS: Hope the English cricketers have better luck against the Irish than you had with this puzzle...

[jimbob]

You are right, this is the original grid as published in the Times today.

[Bernard Stay]

Sudoku Susser couldn't do it because you've made a mistake...

r7c23 cannot have been [86]... I suggest you clear those 2 cells (and all pencilmarks), and start again...

(

Thanks udosuk. Here's the original. I can't find a solution to it, neither can Susser, can you? -

12*|3*7|*5*
6**|**5|**3
***|1**|***
---------------
9*5|**1|*36
***|***|***
86*|5**|9*7
----------------
***|**4|***
5**|8**|**2
*1*|7*6|*48

[udosuk]

Thanks udosuk. Here's the original. I can't find a solution to it, neither can Susser, can you?

No problem at all... After a couple singles and a naked pair:

Code: Select all

 *-----------------------------------------------------------------------------*
 | 1       2       489     | 3       4689    7       | 68      5       49      |
 | 6       4789    4789    | 249     2489    5       | 1278    1278    3       |
 | 347     5       34789   | 1       24689   289     | 2678    2678    49      |
 |-------------------------+-------------------------+-------------------------|
 | 9       47      5       | 24      2478    1       | 248     3       6       |
 | 2347    347     12347   | 6       234789  2389    | 12458   128     15      |
 | 8       6       1234    | 5       234     23      | 9       12      7       |
 |-------------------------+-------------------------+-------------------------|
 | 237     3789    236789  | 29      12359   4       | 13567   1679    15      |
 | 5       3479    34679   | 8       139     39      | 1367    1679    2       |
 | 23      1       239     | 7       2359    6       | 35      4       8       |
 *-----------------------------------------------------------------------------*

There is a swordfish which will crack the puzzle into naked singles... I won't point it out to you. Good luck finding it!

PS: I never thought Susser would be that powerless... Could it be some mistake from you operating it?

[Bernard Stay]

Thanks udosuk. Here's the original. I can't find a solution to it, neither can Susser, can you?

No problem at all.
There is a swordfish which will crack the puzzle into naked singles... I won't point it out to you. Good luck finding it!

You could clear up box 5 because it has a triple. This then leads to my stopping point. But I have no idea what a "swordfish" is. My repertoire goes as far as triples, quads & X-wings. Enlighten?

Thanks.

[udosuk]

You could clear up box 5 because it has a triple. This then leads to my stopping point. But I have no idea what a "swordfish" is. My repertoire goes as far as triples, quads & X-wings. Enlighten?

The triple in box 5 is a valid move but is not required to reach the solution.

I think the Times Super Fiendish puzzles all need the Swordfish technique to solve, so you should really learn it. In fact it's just the 3x3 version of an X-wing.

Here are 2 links which explain it:

http://angusj.com/sudoku/hints.php#swordfish
http://www.setbb.com/sudoku/viewtopic.php?t=617&mforum=sudoku

Please do spend some time reading through them...

Once you learn this technique you should have no problem with all future Times Super Fiendish puzzles...

[Bernard Stay]

I think the Times Super Fiendish puzzles all need the Swordfish technique to solve, so you should really learn it. In fact it's just the 3x3 version of an X-wing.

Once you learn this technique you should have no problem with all future Times Super Fiendish puzzles...

Thanks again. Oddly I've had no trouble with the Super Fs until now!

Perhaps you'll be kind and warn me if I have to start learning Nishios or Fishy Cycles!

I did slightly malign Susser - it could do it but only by invoking "Nishio".

[udosuk]

Oddly I've had no trouble with the Super Fs until now!

Perhaps you'll be kind and warn me if I have to start learning Nishios or Fishy Cycles!

Obviously you haven't bothered to check out the couple of threads below this one...

they say their Super Fiendish may be even tougher than the Pappocom Very Hard puzzles -- possibly requiring Swordfish

How to Solve Superfiendish

• The x-wing technique
  
• The Swordfish technique
  The first puzzle for which it is required appeared in Times2 on Friday, March 16, 2007.

-- when The Times (non-Sunday) wished Very Hard puzzles,
they had to find another source.

and now -- several months later -- they've exceeded the level of Very Hard, allowing Swordfish too.

So, from March 16, 2007 onwards, you need to learn the Swordfish technique if you want to tackle the "Super Fiendish" puzzles...

If in the future they want to add Nishios or Bigger Fishy Cycles such as Jellyfish/Starfish/Squirmbags I'm sure Pat will be kind enough to inform us beforehand... Just keep checking the posts in this forum!

[Bernard Stay]

So, from March 16, 2007 onwards, you need to learn the Swordfish technique if you want to tackle the "Super Fiendish" puzzles...

... Just keep checking the posts in this forum!

Thanks. Will do. But which forum? Pappocom (Scott Gould: email 31 March) tells me that they no longer provide puzzles for the Times or Sunday Times. This forum is labelled 'Pappocom Papers'. Do the forums need rejigging?

[udosuk]

This forum is labelled 'Pappocom Papers'. Do the forums need rejigging?

Perhaps they should rename this section to "Pappocom Papers and Papers which used to publish Pappocom puzzles"...

Anyway I meant this very forum... As long as the adminstrators are kind enough to let us discuss about Times puzzles here...

[richardm]

Interesting - once again swordfish is not required. If you note that (before doing anything else):
r4c4 = 2,4
r6c6 = 2,3
r7c4 = 2,9
r8c6 = 3,9
then you'll see that r4c4 can only be 4. The rest of the puzzle then falls out in seconds.

Incidently, I have yet to see one of the Super Fiendish puzzles that requires swordfish.

Cheers,
Richard

[Pat]

Interesting - once again swordfish is not required. If you note that (before doing anything else):
r4c4 = 2,4
r6c6 = 2,3
r7c4 = 2,9
r8c6 = 3,9
then you'll see that r4c4 can only be 4. The rest of the puzzle then falls out in seconds.

Incidently, I have yet to see one of the Super Fiendish puzzles that requires swordfish.

hey richardm,
you've already indicated your preference for Forcing Chains and Forcing Nets

-- well no puzzle requires Swordfish if you prefer Forcing Nets

[richardm]

Pat, isn't this also known as an xy-wing?

I guess I seem to be able to spot forcing chains and nets more easily than other methods. But I would say, I have yet to come across a Super Fiendish that causes me as much trouble as the old Pappocom Superiors. They were really tought and I wish they would come back.