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Joe Casey
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 7:41 am 
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Did the V1 - nothing new to report: munched through it steadily at first, but N3 and the outermost 45 turned out to be very gristly.
I like to feel we're having to think of something original to solve a puzzle - it's a puzzle, not maths homework - and also I want to feel as if I'm discovering something new, not just following a path set by someone who's been here before (like my motto).
And by the way, no need to put up extra-large pictures on my account: being Scottish, and Scottish thrift is legendary, I print two puzzles to an A4 page whenever possible (KSO pdf pics excepted).
Haven't tried V2.
cheers

PS done V2 now: same deal as V1.
Hidden Text:
got N3 down to 4 prima facie solutions and checked all 4 (it was the first one I found that was right)

cheers again

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Børge
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 2:37 pm 
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Joe Casey wrote:
Did the V1 - nothing new to report: munched through it steadily at first, but N3 and the outermost 45 turned out to be very gristly.
I like to feel we're having to think of something original to solve a puzzle - it's a puzzle, not maths homework - and also I want to feel as if I'm discovering something new, not just following a path set by someone who's been here before (like my motto).
My interpretation of your comment is that the puzzle was below average and not particularly to your liking. Sorry about that.

Joe Casey wrote:
And by the way, no need to put up extra-large pictures on my account: being Scottish, and Scottish thrift is legendary, I print two puzzles to an A4 page ...
Thanks for this information. After your first post in the Assassin 201 thread, asking for more space for or writing the candidates in the corners, I decided to add 150% scaled extra-large pictures. If no one else comes forwards and say that they want them, I will discontinue them.
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Joe Casey
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 2:54 pm 
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No, I wouldn't describe them as below average. They felt original, having to think for oneself and invent stuff, which is good (though maybe subjective); a bit on the hard side of 'comfortable', and not a style I'd like regularly. But I'm not really into stipulating what puzzles are set. Setters choose, and solvers hope for a variety of challenges. I pick the website/newspaper with the sort that suits.
Also: I'm up for one assassin per week, and not greedy for lots of souped-up versions, so I may not let you provoke me into attempting them all in future. Thanks anyway.
And as for Xs and Ys and fish: I'm not against them in principle; I've looked them up and just about understand them; but hardly ever see the opportunity to apply them in puzzles. And if I did, it would be more like maths homework.
All the best,

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Børge
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 3:46 pm 
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Thanks for the feedback.

Joe Casey wrote:
... and not a style I'd like regularly.
What style do you like?
  • Large cages.
  • Small cages.
  • Diagonal cages.
  • Disjoint cages.
  • Zero killer.
  • Combination of two or more of the above.

Joe Casey wrote:
Also: I'm up for one assassin per week, and not greedy for lots of souped-up versions, so I may not let you provoke me into attempting them all in future. Thanks anyway.
When I post more than one version for an Assassin it is manly to try to give people with different solving experiences and skills a treat.
I do not expect anyone to try more than one of the versions, although as you have correctly observed, often tries to provoke the regulars into trying several of them. :D
I also want to have some fun. 8-)

And I really enjoy feedback, and ANY KIND of feedback. One of the main functions of a forum is discussions and the interaction with others.
That's what makes it more fun for me to make Killer Sudoku puzzles than standard gattai puzzles.

I might be wrong, but my impressions is that some of the "big guns" sometimes wants to hone them self and try a really difficult puzzle.

The way I make an Assassin normally produce a lot of puzzles ranging from very easy (SS score 0.60) through absolutely unsolvable (SS score 15.00).
It is therefore very tempting to post them all. It hurts to throw away puzzles.
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Joe Casey
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 5:17 pm 
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What style? Any of these, in any combination, and any others we haven't thought of yet. I value variety, originality and surprises, and my preference is to express no preference.
I think you're right to offer a range of difficulty levels on the same theme (not that you're under any obligation to produce any puzzles at all); sometimes I'm in doubt as to which one to try: usually it'll be the first one rated at over 1.0, which I understand to be traditional Assassin level; but as we know the ratings don't always correspond to subjective difficulty.
cheers

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Last edited by Joe Casey on Thu Oct 28, 2010 5:53 pm, edited 1 time in total.

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Andrew
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 5:42 pm 
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An interesting discussion between Børge and Joe Casey in the last 24 hours.

I like most style of cage patterns, including combinations of the various types listed in Børge's list. One thing not mentioned is that Killer-Xs can go with any of the listed types. Zero Killers are a fairly recent addition to Assassins although they have been around for some time on this site, for example in most/all of HATMAN's puzzles. I've come to enjoy Zeroes, which often bring a different approach to solving.

My preference is for more puzzles with "normal" cages, whether those be large or small, regular or irregular ones and fewer puzzles with diagonal or disjoint cages which tend to give far fewer 45s to work with; diagonal cages within a nonet aren't so bad, they are probably no worse than L-shaped or irregular cages in removing 45s.

Puzzles which require a lot of detailed combination and permutation analysis can be very tedious.

I don't think that I'm one of the "big guns"; most of the people I consider to be in that group aren't active on this site at the moment. I tend to try to solve all posted puzzles "because they are there", to use the proverbial reason for people climbing mountains, and I try to post walkthroughs for the easier puzzles because they may be helpful to Newbies; some of those walkthroughs get linked from my Advice "sticky". As a retired person I've also got more time to work on puzzes, while I'm listening to internet radio which allows me to listen to the BBC even though we retired to Canada. However there can be too many variants on a theme at times; I feel that a maximum of three is reasonable.

As a minimum I try to solve every V1 Assassin but I've still got quite a lot of unfinished harder puzzles, and some not even started, in my Unfinished folders for this site and for Ruud's site.
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Andrew
 Post subject: Re: Assassin 202
PostPosted: Thu Oct 28, 2010 11:06 pm 
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The V2 was a really tough one. After an interesting start I had to resort to chainy combination/permutation analysis so found myself doing what I'll call "solution by attrition".

Rating Comment:
I agree with the SS score. My walkthrough was definitely in 1.75 territory.

Here is my walkthrough for A202V2. I enjoyed this puzzle as far as step 14, then it started getting very heavy going:
Prelims

a) R1C12 = {49/58/67}, no 1,2,3
b) R1C34 = {18/27/36/45}, no 9
c) R23C1 = {29/38/47/56}, no 1
d) R2C23 = {19/28/37/46}, no 5
e) R3C23 = {17/26/35}, no 4,8,9
f) R4C12 = {19/28/37/46}, no 5
g) R45C3 = {69/78}
h) R5C12 = {15/24}
i) R67C9 = {19/28/37/46}, no 5
j) R7C56 = {16/25/34}, no 7,8,9
k) R78C7 = {29/38/47/56}, no 1
l) R78C8 = {39/48/57}, no 1,2,6
m) R89C5 = {19/28/37/46}, no 5
n) R89C6 = {18/27/36/45}, no 9
o) R89C9 = {17/26/35}, no 4,8,9
p) R9C78 = {14/23}
r) 20(3) cage in N7 = {389/479/569/578}, no 1,2
s) Both 45(9) cages = {123456789}

1. 45 rule on N1 1 innie R1C3 = 3, R1C4 = 6, clean-up: no 7 in R1C12, no 8 in R23C1, no 7 in R2C23, no 5 in R3C23
1a. 6 in 45(9) cage at R2C4 only in R6C5678, locked for R6, clean-up: no 4 in R7C9

2. 45 rule on N7 1 innie R7C3 = 1, clean-up: no 9 in R2C2, no 7 in R3C2, no 9 in R6C9, no 6 in R7C56
2a. R89C6 = {18/27/36} (cannot be {45} which clashes with R7C56), no 4,5

3. 45 rule on N9 1 innie R7C9 = 9, R6C9 = 1, clean-up: no 2 in R78C7, no 3 in R78C8, no 7 in R89C9

4. 1 in N9 only in R9C78 = {14}, locked for R9 and N9, clean-up: no 7 in R78C7, no 8 in R78C8, no 6,9 in R8C5, no 8 in R8C6
4a. Naked pair {57} in R78C8, locked for C8 and N9, clean-up: no 6 in R78C7, no 3 in R89C9
4b. Naked pair {38} in R78C7, locked for C7
4c. Naked pair {26} in R89C9, locked for C9

5. 6 in R7 only in R7C12, locked for N7

6. 6 in N8 only in R89C5 = [46] or R89C6 = {36} -> R7C56 = {25} (only remaining combination, cannot be {34} which clashes with R89C5 or R89C6, locking-out cages), locked for R7 and N8 -> R78C8 = [75], clean-up: no 8 in R89C5, no 7 in R89C6

7. 45 rule on N8 3 innies R789C4 = 19 = {379/478}, 7 locked for C4, N8 and 34(7) cage at R6C1, no 7 in R6C123, clean-up: no 3 in R89C5
7a. 3 of {379} must be in R7C4 -> no 3 in R89C4
7b. 45 rule on N6 3 innies R6C123 = 14 = {239/248}, no 5, 2 locked for R6 and N4, clean-up: no 8 in R4C12, no 4 in R5C12
7c. Naked pair {15} in R5C12, locked for R5 and N4, clean-up: no 9 in R4C12
7d. 34(7) cage at R6C1 = {1234789}, CPE no 3,8,9 in R6C4

8. 1 in 45(9) cage at R1C5 only in R1234C5, locked for C5 -> R8C5 = 4, R9C5 = 6, R89C9 = [62], clean-up: no 3 in R89C6
8a. R89C6 = [18], R7C4 = 3, R78C7 = [83], R89C4 = {79}, locked for C4 and 34(7) cage at R6C1
8b. Naked triple {248} in R6C123, locked for R6 and N4 -> R6C4 = 5, clean-up: no 6 in R4C12, no 7 in R45C3
8c. Naked pair {37} in R4C12, locked for R4
8d. Naked pair {69} in R45C3, locked for C3, clean-up: no 1,4 in R2C2, no 2 in R3C2

9. R9C3 = 5 (hidden single in C3), R7C12 = {46} -> R8C23 = 24 – 10 – 5 = 9 = {27}, locked for R8 and N7 -> R89C4 = [97], R8C1 = 8, clean-up: no 5 in R1C2
9a. Naked pair {27} in R38C3, locked for C3, clean-up: no 8 in R2C2

10. R3C2 = 1 (hidden single in N1), R3C3 = 7, R8C23 = [72], R4C12 = [73], R5C12 = [15], R9C12 = [39], clean-up: no 4 in R1C1, no 4 in R23C1

[It’s now possible to do a forcing chain, based on the candidates in R6C1, to eliminate one candidate from R6C2. I’ll leave that for now because it doesn’t contribute toward progress.]

11. 5 in 45(9) cage at R1C5 only in R123C5, locked for C5 and N2 -> R7C56 = [25]
11a. 2,6 in 45(9) cage at R1C5 only in R5C678, locked for R5 -> R45C3 = [69]
11b. 9 in 45(9) cage at R1C5 only in R1234C5, locked for C5
11c. 7 in R5 only in R5C5679, locked for 45(9) cage at R1C5, no 7 in R12C5
11d. 7 in N2 only in R12C6, locked for C6

12. 38(7) cage at R1C6 = {2345789}, 3,7 locked for C6 and N2

13. Naked quad {1589} in R1234C5, 8 locked for C5 and 45(9) cage at R1C5, no 8 in R5C589
13a. R5C4 = 8 (hidden single in R5)

14. 24(4) cage in N3 cannot be {1689} (because 1,6,9 only in R12C8) -> no 1 in R12C8
14a. 1 in N3 only in R12C7, locked for C7 -> R9C78 = [41]

15. 24(4) cage in N3 = {2589/3489/3579/3678/4569/4578} (cannot be {2679} because 2,6,9 only in R12C8)
15a. 4,9 of {3489} must be in R1C89 (R1C89 cannot be {48/89} which clash with R1C12), 4,9 of {4569} must be in R1C89 (R1C89 cannot be {59} which clashes with R1C1), 5,7 of {4578} must be in R12C9 -> no 4 in R2C9

16. 21(5) cage in N3 (from combinations for 24(4) cage, step 15) = {12369/12378/12459/12468/12567/13467}
16a. 5 of {12459} must be in R3C79 (R12C7 cannot be {15} because R5C789 cannot be {249} which clashes with R3C4), 1,7 of {12567} must be in R12C7 -> no 5 in R12C7

17. 21(5) cage in N3 (step 16) = {12369/12378/12459/12468/12567/13467}
17a. {12369} => R3C5 = 8 (hidden single in R3) => R3C1 = 5 (hidden single in R3) => R2C1 = 6 => 6 of {12369} not in R2C7
1,7 of {12378/12567/13467} must be in R12C7 => killer pair 2,4 in R3C4 and R3C789, locked for R3
{12459/12468} => two of 1,2,4 must be in R12C7 and the other in R3C789 (R3C789 cannot contain both of 2,4 which would clash with R3C4) => killer pair 2,4 in R3C4 and R3C789, locked for R3
-> no 6 in R2C7, no 2 in R3C1, clean-up: no 9 in R2C1

18. 2 in N1 only in R2C12, locked for R2

[Now for some heavier chaining of permutations.]

19. 5 in N3 can be in either 21(5) cage or 24(4) cage
24(4) cage (step 15) = {2589/3489/3579/3678/4569/4578}
21(5) cage (step 16) = {12369/12378/12459/12468/12567/13467}
19a. 5 in 24(4) cage = {2589/3579/4569/4578} must be in R12C9 => no 5 in R4C9
Consider now the two other combinations for the 24(4) cage
24(4) cage = {3489} => 21(5) cage = {12567} => R3C9 = 5 => no 5 in R4C9
24(4) cage = {3678} = [8763] => R5C9 = 4, 21(5) cage = {12459} => R3C9 = 5 => no 5 in R4C9
-> no 5 in R4C9
19b. R4C7 = 5 (hidden single in R4)

20. 21(5) cage in N3 (step 16) = {12369/12378/12459/12468/12567/13467} cannot be {12459}, here’s how
{12459} = [21945] (cannot be {19}[245] which clashes with R3C4) => R23C1 = [56] => R1C1 = 9 => 1,5 in R1 only in R1C5
20a. -> 21(5) cage = {12369/12378/12468/12567/13467}
24(4) cage = {2589/3489/3579/4569/4578}

21. 21(5) cage (step 20a) = {12369/12378/12468/12567/13467} cannot be {12567}, here’s how
{12567} = {17}{26}5 => 24(4) cage in N3 = {3489}, R23C1 = [29] => R1C12 = [58], R3C45 = [48] (hidden singles in R3), R2C4 = 1 => R1C5 = 9 clashes with 24(4) cage
21a. -> 21(5) cage = {12369/12378/12468/13467}, no 5
24(4) cage = {2589/3579/4569/4578}
21b. 5,7 of {3579} must be R12C9 -> no 3 in R2C9

22. 21(5) cage (step 21a) = {12369/12378/12468/13467} cannot be {12378}, here’s how
{12378} = {17}2{38} => R3C4 = 4 => R2C4 = 1, 24(4) cage in N3 = {4569} = [9465] (R1C89 cannot be [95] which clashes with R1C1) => R1C12 = [58] => no remaining candidates for R1C5
22a. -> 21(5) cage = {12369/12468/13467}, 6 locked for R3 and N3, clean-up: no 5 in R2C1
24(4) cage = {2589/3579/4578}
22b. 5,7 of {4578} must be in R12C9 -> no 4 in R1C9

23. 24(4) cage (step 22a) = {2589/3579/4578}
5,8 of {2589} must be in R12C9 => R4C9 = 4 => R3C9 = 3
3 of {3579} must be in R2C8
{4578} => 21(5) cage = {12369} => 3 of {12369} must be in R3C9
-> no 3 in R3C8

24. 24(4) cage (step 22a) = {2589/3579/4578}
24a. {2589} => R1C8 = 2, R2C8 = 9, R12C9 = {58} => R4C9 = 4, 21(5) cage in N3 = {13467} = {17}[643], R3C4 = 2, R3C6 = 9, R3C1 = 5, R1C1 = 9, R1C2 = 4, R2C3 = 8 => R2C9 = 5
5 of {3579} must be in R2C9 (R1C89 cannot be [95] which clashes with R1C1)
4,8 of {4578} must be in R12C8 => naked pair {48} in R2C38, locked for R2 => R2C4 = 1, naked pair {48} in R1C28, locked for R1 => R1C5 = {59} => naked pair {59} in R1C15, locked for R1
-> no 5 in R1C9
24b. R2C9 = 5 (hidden single in C9)

25. 24(4) cage (step 22a) = {2589/3579/4578}
{2589} = [2895] => R1C2 = 4, R1C1 = 9 => R1C6 = 7
7 of {3579/4578} must be in R1C9
-> no 7 in R1C7

26. 24(4) cage (step 22a) = {2589/3579/4578}
26a. 8 of {2589/4578} locked in 24(4) cage => no 8 in R3C9
{3579} = [9735] => 21(5) cage = {12468} = [216]{48} => R1C6 = 4 => R4C9 = 8
-> no 8 in R3C9

27. 21(5) cage (step 22a) = {12369/12468/13467}
27a. {12369} cannot be [21]{69}3, here’s how
{12369} = [21]{69}3 => R3C1 = 5, R1C1 = 9, R1C2 = 4, 24(4) cage in N3 = {4578} => R1C9 = 7 => no remaining candidates for R1C6
27b. -> {12369} = {19}{26}3, no 9 in R3C78
27c. 2 of {12369} must be in R3C78
4 of {12468/13467} must be in R3C9 => R3C4 = 2
-> no 2 in R3C6

28. 21(5) cage (step 22a) = {12369/12468/13467} cannot be {12468}, here’s how
{12468} = [21684] => R5C7 = 7, R5C9 = 3 (hidden single in C9) => R5C79 = [73] clashes with R5C5
28a. -> 21(5) cage = {12369/13467}, no 8 -> R3C9 = 3
28b. R2C6 = 3 (hidden single in N2), R3C5 = 8 (hidden single in R3)
28c. 4 in C9 only in R45C9, locked for N6

29. Naked pair {19} in R24C5, locked for C5 -> R1C5 = 5, R1C1 = 9, R1C2 = 4

30. Naked triple {149} in R2C45 + R3C6, locked for N2 -> R3C4 = 2

and the rest is naked singles.

Congratulations to Joe Casey for solving this V2 with paper and pencil. :applause: I used coloured candidates on my worksheet to keep track of the analysis which I was doing and, even then, found I had to re-work part of one sub-step when I checked my walkthrough before posting it.
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