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Explosion 30

Posted: Fri Feb 02, 2007 3:58 pm
by lynn893
Ruud, on a rating of 'very hard', what solving methods are needed????

(So far, after doing all techniques that I know of [hatching, locked candidates, triples, 2 quads, etc.] and going as far as I can (through each of the grids numerous times, I'm at a dead end and not even 1/5 of puzzle done).

I'm going to have to start guessing soon.... logically of course.

:oops: :? :cry: :x

Posted: Fri Feb 02, 2007 6:57 pm
by Glyn
Hi Lynn

I used TRYfurcation, I'd love to know if anyone found a more logical approach.

:?

Posted: Fri Feb 02, 2007 7:21 pm
by Ruud
A very hard Clueless (explosion) can have:

- Line-box reductions, (center-dot reductions)
- Naked pairs, triples, quads
- Hidden pairs, triples, quads
- X-Wing

It also has a strong interaction between the central puzzle and the 9 constituent puzzles. In this case, you need to solve 7 of 9 constituent puzzles before you can complete the "blue" grid.

Ruud

Posted: Sat Feb 03, 2007 1:38 am
by lynn893
[quote="Glyn"]Hi Lynn

I used TRYfurcation, I'd love to know if anyone found a more logical approach.

:?[/quote]

Never heard of that technique... can you elaborate on it? As of right now, I'm using 'logical guessing' :P Is it the same?

Ruud, I'm stuck.... not sure if I'm going to make the lists this week unless I get really pi$$ed off at this explosion and go back to the solving guide and try to figure out some of those techniques that you guys are all so good at. :cry:

Posted: Sat Feb 03, 2007 9:27 am
by Glyn
Because the unknowns that make each of the nine constituent Sudokus insoluble are the missing centres of the blocks, I picked one Sudoku and tried some combinations. I was lucky, in that the reduction in the possible candidates gave some line box reductions in the central puzzle and the whole thing dropped out from there.

I can't remember which constituent Sudoku I worked with, but the ones with the least options for the centre spots seem promising.

TRYfurcation is a play on words (more desperate than bifurcation). :lol:

Posted: Sun Feb 04, 2007 12:44 am
by lynn893
I DID IT!!!!

Whew, that was the toughest sudoku I've EVER done.

Ruud, my husband and my children are severly pi$$ed at me because I've completely neglected everyone and everything (with the exception of meals and emergency situations) for the past 3 days while I figured this one out. :P

No, seriously, that was one tough explosion. I think I ended up doing 5 sets of biwhatever (logical guessing is what it comes down to) from grid 10 to end up sorting this one out.

I think the next update for the Clueless helper should be some solving techniques (like SudoCue) has [ie: coloring would be a great addition to the helper)

:D

I can go and relax now (or get cleaning!) mmmm, relaxing sounds good after this stressful explosion.... :D

Posted: Mon Feb 19, 2007 4:34 pm
by Pete
coloring

This was a hard one .

i could make no progress at all until i started looking at center dot intersections.

That still doesnt make it easy but it made the crucial start

Posted: Wed Feb 21, 2007 8:21 pm
by Princess Amy
I'm not familiar with most of the techniques yet, but I solve these. I only know the hidden and visible duets/ trios/quartets, swordfishes, and the unique pairs, and I get through them.

This time, I had a unique pair thing with two numbers, I think 7&9, that was shaped like a swordfish.

When I get stuck, I go back to the center dots in the blue sudoku. I wish they turned colors or eliminated the ones that are already used, but I think that request goes in a different area.

:princess: Amy Grace

Posted: Wed Feb 21, 2007 9:29 pm
by nj3h
Ruud,
Previously you posted that the subject puzzle can be solved with the techniques listed below.

====================

A very hard Clueless (explosion) can have:

- Line-box reductions, (center-dot reductions)
- Naked pairs, triples, quads
- Hidden pairs, triples, quads
- X-Wing

It also has a strong interaction between the central puzzle and the 9 constituent puzzles. In this case, you need to solve 7 of 9 constituent puzzles before you can complete the "blue" grid.

=====================

I am reading other messages that indicate coloring, unique pairs, etc were used. Of course, one could always use a higher lever technique if found, but I presume that for this puzzle only the techniques listed in your previous message are needed.

Regards,
George

Posted: Wed Feb 21, 2007 9:51 pm
by Ruud
George,

you are correct. In my program for creating these overlapping puzzles, only those listed techniques are implemented. Other techniques may be useful for players who master them (especially coloring), but the puzzles are always solvable without them.

cheers,
Ruud

Posted: Thu Feb 22, 2007 1:51 am
by nj3h
Hi Ruud,

Just curious if your overlapping program can create puzzles with specific techniques required (or allowed) like SudoCue? In other words, have you set it up where you pick the techniques from a list or are they just hard-coded into the program?

These overlapping puzzles are just great. They are a whole new world of fun. Don't let your overlapping puzzle generator get rusty.

Regards,
George

Posted: Thu Mar 01, 2007 4:26 pm
by Glyn
Kept trying this to see if simple techniques would work and eventually confirmed that was true.

Watch out in the constituent puzzles for candidates in the centre spots locked in a row or column, these eliminate other occurences in that row or column. I had always checked those when I saw candidates locked to a row or column in a box of the Clueless grid.

This time I needed to check for candidates in a row or column locked in the centre spots, this eliminates other occurences in the centre spots outside that row or column. That is a little trickier to spot as you don't have the clueless grid to help you.

Hope this helps. Perhaps Ruud will write a guide to variants at some point in the future, haven't seen much on that anywhere.