I totally agree that this test had the simplest of answer keys. And, most of the solvers had to spend only a few seconds to input the answer keys.

But, at the same time, the answer key also became much more prone to guessing - not for all puzzles, but for specific ones. If you had solved a little of these puzzles, you could guess the answer key with a fair chance of success. According to me, the puzzles which fell into this category were the ones which involved counting in certain rows/columns (eg hitori, shikaku, akari, etc).

Because of the answer key, in the end, I was encouraged to make guesses for broken or even almost blank puzzles. I made 4 guesses and got 2 right - for a total of 48 points. Thats almost 10% of points.

So, question to ponder: should we make the answer key just a bit harder - for counting based answer keys?

Overall, a very enjoyable set of puzzles. I specially liked the new types - Shakashaka and Mochikoro - as never saw them before. Thanks to the puzzle team for an excellent test. And, Congratulations for the most successful test yet on LMI !!! (in terms of participation)

I also think you deserve some bonus points. But did you click on "Claim bonus"?

Can you also share the secret here, as I am not able to make anything out of it? (I initially thought something to do with Roman numbers, but there is no W in Roman numbers.)


Edited by rakesh_rai 2011-08-22 1:31 PM

A lot of giants was here. I always remember my perfect zero score on giant part in Minsk 2008.

I hope this is not a future of the puzzles. Try to imagine such sudoku contest with every second 12x12, 16x16 puzzle or larger. I think it wouldn't be interesting. Anyway, thanks to the authors. Also, I learned something about the history of the puzzles.

Nikola

Solution Booklet - http://logicmastersindia.com/lmitests/dl.asp?attachmentid=172&v1

It also has who created which puzzle and some interesting links.

Didn't we have similar answer keys in other tests, especially in Nikoli Selection 2011?

Well, I'm not sure about other competitions, but we unlikely to have 12X12 / 16X16 Sudokus in a Sudoku contest. (Our flash doesn't support it :-)

Regarding puzzles : We generally don't have large puzzles in LMI tests. But 'larger' puzzles are part of Nikoli's tradition. So I thought having slightly larger puzzles will appropriately represent how Nikoli's puzzles are.

I mentioned the same (as a test solver) - e.g. hashi in NS2011 was a very guessable answer key.

Thanks for pointing out. We adopted simple answer keys because we would like competitors to concentrate on solving, not counting. But we must admit that some of them were too simple and easily guessable. We will consider their balance more carefully next time.

P.S. At first, answer keys for Slitherlink, Masyu, Shikaku and Yajilin+ were much simpler. I asked authors to change them.

I see a difference between the large puzzles here and many of the Giants part in Minsk 2008. Basically, there are some puzzle types that, for the most part, are locally solvable meaning that the difficulty mostly scales with the number of cells. There are other puzzle types that use more global constraints and get much harder as the size increases. Sudoku is certainly in this category, as are the types Tents, Star Battle, and Pills from Giants in 2008 that get much much harder as the size increases.

But puzzles like Kakuro, Slitherlink, Masyu, Heyawake and others that went "big" here are not types that require you to think about the whole grid at one time very often if at all. The size makes it more of a challenge of not making mistakes (as errors will eventually propagate and cause trouble), but it still scales with the overall size of the puzzle. On Nikoli.com, I call these "larger but not harder" puzzles. And this test matched the Nikoli style perfectly well where most of the hards that are 14x24 are as challenging as a 10x10 hard puzzle, but take 336/100 times the time.

Edited by motris 2011-08-22 8:48 PM

I read all comments. Thanks for posting how you felt about the test.

Puzzles: In making Nikoli test, we had two options about difficulty and grid size:
(A) only small grids (8x8 -- 10x10), from easy to extra hard [WPC standard]
(B) from small to big, from easy to hard [Nikoli standard]
Authors adopted (B), because they wanted to think highly of Nikoli style. We are confident that we presented one aspect of good puzzles/competitions.

One of the purposes of this test was to popularize a new puzzle (Shakashaka) and an old puzzle (Mochikoro). That is why we included some practice puzzles for these types. We are very pleased to know 89 solved Mochikoro (Top) and 59 solved Shakashaka (Top) correctly.

Timing: My test-solving time was 80:14. This includes checking time for most puzzles, but without competition pressure and answer entry. Competition time was decided considering authors' intention and my time. This was a little short especially for those who are not familiar with Nikoli puzzles, but we were relieved when motris solved all puzzles correctly. Apart from motris, MellowMelon solved 25 and xevs solved 24, but both of them made mistakes in high pointers.

Password: This is the only puzzle I made for this test. It is a verbal arithmetic problem with a unique solution (no leading zeros). M and W represent specific values with respect to the date when this test was held.

Also motris and xevs started the test almost at same time (may be 5 minutes apart). It was really interesting watch their submissions (both of them submitted each puzzle after solving). After 70 minutes into their starts, motris had 391 points and xevs had 390 points.

I'm starting to really like the shakashaka puzzles. I think the triangled grid works much better for solving purposes for me. The normal grid I am not really sure how to keep notes. I didn't like them the first time I saw them as I always messed up notationwise (somewhat like corral, which had the same problem at first). Don't think I'm the only one who feels this way, but I think it's a better way to represent them, if you want to try to make it more popular.
Mochikoro I was a litle less a fan of as it seems very intuitive a genre. While solving the big one afterwards I kept feeling intuitively where rectangles had to go, because I couldn't see how it would turn out unique otherwise. I did it logically eventually, but those thoughts somewhat clash with an enjoyable solve as I want to do it logically.



Think the timing was good. I know, I'm not a quick big puzzle solver, so knew I wouldn't be in the top. Just missed out of the top 20 as the timer ran out when I was about to click submit on the larger heyawake. I used the test a bit to practise puzzle I never really solve: namely akari, heyawake and the 3 new ones. Still learning the tricks and patterns on akari and heyawake. Love to get some pointers on them at one point. Feel like I'm missing a lot of things still.



I understand why it was done. Have no problem with it. Just know that without a regular Nikoli practise on puzzles this size, it's harder to do them fast. the designs all were okay for a fast solve. Still got stumped by puzzles I normally wouldn't have a problem with in smaller size (masyu/slitherlink).
I'm still not too sure about the kakuro points though, as I was faster in my kakuro solve for the small one than the big one. But that might be because I make a lot of these hard small puzzles and quickly recognise the breaking points in hard kakuros.