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daj95376 · Joined: 23 Aug 2008 Posts: 3854

Added challenge: perform eliminations in only one candidate value for VH and VH+ techniques.

tlanglet · Posted: Wed Jan 27, 2010 12:58 pm Post subject:

My first attempt to complete this challenge was not successful. I made four moves eliminating 3s, but it was not possible to complete the puzzle with another deletion of a 3. In any case, I found it a very interesting, fun puzzle and will try again. My first solution had two interesting moves that I assume are VH+, as follows.

x-wing 3 in r28c34 deletes 3 in r2c25|r8c56,

sashimi swordfish 3 in r345c268 deleted 3 in r6c2,

Kraken x-wing 3 in r57c16 and fin in r5c8.
If x-wing is true then 3 is deleted from r6c1|r146c6,
If fin is true: (3)r5c8 - (3)r13c8 = (3)r1c9; r1c6 <>3,
If fin is true: (3)r5c8 - (3)r13c8 = (3)r1c9 - (3)r1c5 = (3)r6c5; r6c1|r46c6<>3. Thus all four deletions are made by the x-wing and the fin and can be removed.

x-wing 3 in r34c28 deletes 3 in r1c28|r5c8,

At this point, no further deletions of 3 are possible. A xy-wing 1-23 with vertex 13 in r3c8 completed the puzzle.

Ted

tlanglet · Posted: Wed Jan 27, 2010 1:39 pm Post subject:

Well, I make another pass at meeting this challenge with digit 3 and found a more normal sequence of steps but it resulted in the same final condition as my first attempt.

So I gave up on digit 3 and tried another digit which also failed after several encouraging moves. I am obviously missing the key to open up this puzzle.

Ted

daj95376 · Joined: 23 Aug 2008 Posts: 3854

The puzzle is "tricky" but not unreasonable in the steps needed. There is only one VH+ step needed.

Ted: When an XY-Wing performs an elimination in a bivalue cell, then the XY-Wing can be "slid around" to perform a complementary elimination in one of the original pincer cells.

arkietech · Posted: Wed Jan 27, 2010 3:34 pm Post subject:

Fun puzzle! Very Happy

Marty R. · Posted: Wed Jan 27, 2010 11:08 pm Post subject:

As usual, I just play the moves I see.

XYZ (369), maybe a non-factor
X (3)
Kite (3)
Hidden UR (15), a non-factor
XYZ (123)
Simple coloring (3)

daj95376 · Joined: 23 Aug 2008 Posts: 3854

I consider it "tricky" when an X-Wing for a candidate value immediately exposes a second X-Wing for that candidate value. I'm "completely unprepared" to later encounter a third X-Wing for that candidate value. An asterisk (*) marks the VH and VH+ steps for candidate <3>.