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peterj · Joined: 26 Mar 2010 Posts: 974 Location: London, UK

These both seem really tough! After a couple of opening UR moves I am already on Sashimi Swordfish and making no progress - and that's the non-salsa one - must be missing something.
Time to go to work...

Mogulmeister · Joined: 03 May 2007 Posts: 1151

Somewhat different but a nice puzzle. Well the non salsa anyway........

peterj · Joined: 26 Mar 2010 Posts: 974 Location: London, UK

Mogulmeister
Ah! I never tried group colouring (note to self!) but yes there is a nice grouped x-cycle on 2...

(2)r9c7=r9c12-r7c3=r6c3-r4c2=r4c7-r9c7

I managed some of these eliminations with a finned swordfish and sashimi swordfish.... but this is much better!

I don't know why I found this so difficult. Just sometimes you dont see the wood from the trees..

Mogulmeister · Joined: 03 May 2007 Posts: 1151

Like you peter, I normally tend to investigate colouring/strong-link polarisations first before moving on as experience to date has shown this to be quite a good early move. Mind you lately All sorts of things, (many unproductive) have taken up residence in my Sudoku Top Trumps deck!

tlanglet · Posted: Wed Apr 28, 2010 2:57 pm Post subject:

Here is my offering for still another variation of the solution for the initial puzzle.

UR68 in r12c49 strong link 6 in row2 & col4; r1c9<>8, which opens a

hp(68)r25c9 = nt(349)r5c139 - (9=6)r5c8; r6c9<>6,
(In verbage, hp(68)r25c9 = (39)r5c9 forms nt(349)r5c139 which deletes 9 in r5c8 making it equal to 6. Thus, r6c9<>6.)

UR67 in r45c57 with x-wing 7; r45c7<>6,

Flightless finned x-wing 2 in r49c27 with fin in r9c1. Note the fin is in a box that contains one of the x-wing cells, but no other candidates for deletion exist in the box. However, by treating the fin as a Kraken fin/cell we get (2)r9c1 - r7c3 = (2)r6c3; r6c27<>2 and continuing the chain (2)r6c3 - r6c79 = (2)r4c7; r13c7<>2, which are also four of the five deletions provided by the x-wing

A short AIC found extending the vertex of a potential xy-wing: (3=6)r6c2 - (6=2)r4c2 - (2=7)r4c7 - (7=8)r5c7 - (8=3)r5c9; r5c13|r6c9<>3.

Ted
[Edited to correct the number of deletions by the x-wing]

tlanglet · Posted: Wed Apr 28, 2010 9:45 pm Post subject:

My solution for the second version is similar to the first puzzle with a twist here and about.

skyscraper 4 r9c26; r1c5|r2c1<>4,

UR68 in r12c49 strong link 6 in row2 & col4; r1c9<>8,

hp(68)r25c9 = nt(349)r5c139 - (9=6)r5c8; r6c9<>6,
(In verbage, hp(68)r25c9 = (39)r5c9 forms nt(349)r5c139 which deletes 9 in r5c8 making it equal to 6. Thus, f6c9<>6.)

hidden UR 67 r45c57 with x-wing 7; r4c7<>6

x-wing 2 with two separate fins in r49c27 and fins in r9c1 r4c8
If x-wing true; r16c2|r136c7<>2
if r9c1=2: (2)r9c1 - r7c3 = (2)r6c3; r6c27<>2 and continuing the chain (2)r6c3 - r6c79 = (2)r4c7; r13c7<>2,
If r4c8=2: (2)r4c8; r6c7<>2
Thus, r6c7<>2

(3=8)r5c9 - (8=7)r5c7 - (7=2)r4c7 - np(26=3)r46c2; r5c13|r6c9<>3

(3=2)r6c3 - r4c2 = r4c8 - (2=4)r1c8 - (4=3)r1c2; r6c2<>3

Ted

Marty R. · Posted: Wed Apr 28, 2010 10:13 pm Post subject:

ER (2)
XYZ-Wing (236)
Roof cells of UR (24) form 69 pseudo cell as part of a naked pair.

daj95376 · Joined: 23 Aug 2008 Posts: 3854

Marty: Nice catch on that slippery ER. I was wondering if everyone was going to be forced around it and the Naked Pair => XYZ-Wing to crack the puzzle.