I think that the X-sums in the IB has an alternate solution. Not sure if I can attach a screenshot, so I'll write out the alternate numbers:

846957
759864
597486
468795
975648
684579

I guess I have another clarification question for X-Sums. Can a clued row or column begin with a number that exceeds 6? If so, would the total be the same as though it were a 6?

It cannot exceed 6.

Great contest, loved the concept, thanks Rakesh!

It was tough because I felt I rarely had time to really think about a puzzle (though maybe I should have?) and was constantly in experimental mode. Might have finished if I hadn't wasted time with being unsure/unaware of constant arithmetic sequences, but the Little Killer seemed impenetrable. I worked it out cleanly afterwards, and there's a fair path -- I imagine the same would be true of the various puzzles where I wasn't even close to finding that.

Alright, so before I discuss my solving experience, I should mention that I've made a habit of solving LMI sudoku competitions exclusively through the online interface. Sometimes I find myself questioning that decision, partly because I think I'm a bit faster on pencil and paper despite the extra time keying in solution codes, and partly because I worry that without specialized notation, individual puzzles might slip out of my grasp. (They generally don't, but they still have the potential to do so.)

This competition has me feeling very mixed emotions about that decision, because on one hand, there were several times when I found myself sorely missing such notational methods. But on the other hand, necessity is the mother of invention, and I wound up adopting an aggressive trial-and-error approach that would have been a total mess on paper -- I've never made so much use of the Reset button. I could never have gotten away with doing it on 9x9 grids, but in this particular scenario (6x6, incomplete number sets to work out) doing lots of guesswork paid off startlingly (disappointingly?) well at times. I might like to revisit some of the harder puzzles later and figure out how to actually solve them rather than just stumbling onto the right set of digits by making assumptions. The Kropki in particular fell pretty fast to "Let's just assume this square is also 7".

It felt like an accomplishment to finish the round, and yet it didn't feel like I'd truly earned the accomplishment. It's a strange feeling -- not necessarily unwelcome, because the experience was quite a thrill ride, but decidedly different than what I'm accustomed to. I enjoyed it, (EDIT: I also really loved the concept of the round), and I'd be okay with experiencing a round like this one again (ideally in a similar 'off-week/casual' setting), but if I ever find myself resorting to flat-out trial and error this much at a WSPC round I might wonder if I'm irrevocably past my prime. :-P

Setting aside the dirty, dirty feeling of guessing my way through so many puzzles in one session, I should mention that Sequence felt particularly overvalued -- I skipped past it at first because I thought I was a bit short on time to risk it, then came back later and quickly steamrolled through the full solution path in just over 3 minutes. Its difficulty is almost entirely contained in the "same digit repeated is an arithmetic progression" a-ha moment, which feels like the puzzling equivalent of a trick question; to its credit, the puzzle made eliminating all other options for that line incredibly efficient, so it was probably the best possible execution of that trick, but 9 points still felt like too great a reward for spotting it so quickly.

Edited by ByronosaurusRex 2020-05-09 5:36 AM

Thanks Rob! Constant arithmetic sequences would always be in the doubtful category, unless explicitly mentioned elsewhere. That is the reason the IB example had one sequence of 999.

I will share the (intended) starts for each puzzle later.

Very nice contest Rakesh. I loved the path for each Sudoku i solved. I never looked at the IB and never realized about the Constant AP. Wasted a lot of time (more than 20 min) and at last realized that it should be broken????.
After the contest saw the IB.

Great test though..

Way, way, way too hard for a timed test in my opinion...but the few I solved seemed like nice puzzles. I try to avoid trial and error when possible but barely got started. Regular killer took almost 40 minutes. Fumbled with kropki about 15 minutes, got nowhere. Couldn't even begin little killer. Lost interest, walked away and made a cup of coffee...I'll save the rest for a rainy Saturday sometime.

It appears to me that there are 2 solutions to 09 Odd Even Count using the digits 1, 2, 3, 5, 7, 9. The corner circles are 3s and the interior circles are 7s. The two solutions would arise by swapping the 1s and 2s in columns three and six.

Have I missed something here?

You may be missing the rule that all circles are marked, meaning that no digit can follow the count properties if it isn't in a circle.

Thanks Prasanna! I had forgotten thank requirement. That eliminates one of the solutions.

I think it's a very cool competition. I really enjoyed ! But I also agree this guessing part many have mentioned here before me.

Thanks for a nice change from the PRs and SMs, Rakesh.
I didn't pay attention to the IB's Sequences example and lost some time to figure out +0 is a valid arithmetic progression.
You could see a lot of clever intended paths - showing how meticulously these were made.
Unfortunately, as Byron noted, the 6x6 nature made this test prone to guessing for one to solve as many grids as possible in the 90 minutes.

Good fun nonetheless. Thanks again!

For every high-pointer, there would be some participants who do it in a quicker than expected time. For sequence, based on the observations so far, participants have indeed taken some time before realizing that 3-3-3-3 sequence as a possibility. Since 1 and 2 are not possible on the longer line, 3456 seems a more natural sequence everyone would go for, and then reach a contradiction. I agree it is not a complex deduction but still takes time somewhere.

Password is sent by mail?

Thanks for a wonderful contest Rakesh .Monthly contests are a rarity nowadays and it was a pleasant sight to see a sudoku contest aside from the routine of SM & PRs. This contest made me reminescent of ISC 2016?! wherein Round 4 (authored by Deb)had 6x6 sudokus with unknown list of digits in which I scored 43 and you 133 (if I am not wrong and my memory is good.I am unable to get the result list for the same to verify) and you edged ahead of me to podium.

I would be curious to know your inspiration for writing this test and whether you got the idea by the above mentioned round.About the contest itself, the sudokus were definitely on the harder side and will be extremely fun to solve as one-offs without contest time constraints or pressure. In the contest, I had to guess on most but I did find logic in a few and they were very interesting. Thanks again ! Hope we get to see more monthly contests in LMI !

It is displayed on the screen once you start the contest. It seems you already took the test. So you would be knowing this already.

Very interesting set of puzzles. It was certainly very challenging trying to find out the digits by solving , but made it more fun too. i wish I was less sleepy and had a printer since I took time solving online. Thanks for a very innovative contest.

Those puzzles were really hard, but very fun! I wish I had had more time, but I enjoyed solving what I could in the time allotted. Thanks very much Rakesh!

Thanks Rakesh for Mean Minis! They were a wonderful set of moderate to hard puzzles with very interesting solving paths. Thoroughly enjoyed.

The Solution Booklet is now available here.