Indian Sudoku Championship, 2025

Last weekend I participated in the Indian Sudoku Championship and Sudoku Mahabharat playoffs organised by Logic Masters India at Kolkata. I'm happy to share that I finished 8th in the Indian Sudoku Championship and 2nd in the Sudoku Mahabharat😀

It was a wonderful day of meeting some long-time friends, getting to know a few new sudoku solvers, participating in the contest as well as fun event, celebrating the birthday of Kumaresan sir, participating in the Sudoku Mahabharat playoffs and a lot more!

Before I go into recounting the experience by each round, I would like to thank Prasanna for curating the sudokus for the event, the sudoku authors [Bill Murphy (Australia), Chandrachud Nanduri (India), James Peter (India), Madhav Sankaranarayanan (India), Nikola Zivanovic (Serbia), Philip

Newman (USA), Prasanna (India), Wessel Strijkstra (The Netherlands)], the on ground team (Subham, Priya and Neha), Priyam for organising the fun event and the volunteers. 

Below I share my experience of participating in the championship. 

The first round had 8 Classic Sudokus, 1 Overlapping Sudoku and 1 Sudo-Kurve. I started with the 5th and 6th classic and could easily complete them. Then went on to Overlapping and Sudo-kurve as they were highest pointers. Though I took some time, I could complete those two and moved on to the high pointer classics - 35 and 50 points. To complete faster I guessed in both of them and fortunately both my guesses turned out to be correct. Then I finished three more classics and was left with just one sudoku unfinished when the round ended. I was really happy with how the round went for me only to realise that I had made silly mistakes in both the Overlapping and Sudo-kurve to lose 125 points! 

Below is a snap of the error I made in Sudo-kurve. See those two circled 8s. I would have gotten 70 points if I had written a 7 instead of the upper 8😑

Nevertheless, then came the 2nd round. This round had 8 sudoku variants from different Sudoku Mahabharat rounds. I started with the Thermo Sudoku, was making slow but good progress but ended up breaking it. But I decided to give it another try and this time I was able to complete the sudoku. Then went on to the Disjoint Sudoku. Though slowly, I could finish this as well. Next I started Battenburg sudoku. This one involved making a lot of odd-even markings but was a good solve. I aimed to do the 70-pointer irregular after this but unfortunately broke it. I had only 2 mins left. I thought to give the low pointer The Greater Sudoku a try but couldn't complete it in time. This round was also okayish and I wasn't much happy. After this round I was at 10th position. 

The 3rd round had 10 variants to be completed in 60 minutes. I started with the Palindrome. It had a long Palindrome with a good pair and an overall good solve path. Then I went on to the Pandigital Sums Sudoku. In his stream on LMI Discord channel Prasanna had mentioned that there was some trick to solve this variant but I couldn't figure it out and asked him before the contest. With the trick, it was approachable. Not sure if I could have completed it without knowing the trick. Next I solved the 90 pointer German Whispers (after breaking it once), 55-pointer Outside 234 Sudoku and 25-pointer Parity Lines Sudoku. With very little time left, I made an unsuccessful attempt at 45-pointer Disparity Sudoku. But overall, this round went well. After this round I came up to 8th position. [Looks like there is some connection between me and 3rd round of ISC - last year also this was the round which lifted me up😉]

Then came the 4th round which had 12 interconnected sudokus! And did I perform badly at this round! I made a decent start with the top 3 sudokus but then kept on breaking the 4 sudokus at the bottom right. I broke them 4 times and could complete only 2 sudokus out of the 12 getting a horrible score of 50/320. But fortunately I still maintained the 8th position!

And I also qualified for the SM playoffs! I started with the 2nd seed position. The 3rd-5th seed playoffs started with Tushar, Pooja and Akash. Tushar advanced to the 1st-3rd seed playoffs between Harsh, myself and Tushar. I took a lot of time in the Thermo sudoku, broke it in between, solved it again. But then I solved the mastermind sudoku quite quickly and finished 2nd in the Sudoku Mahabharat. 

With this the Indian Sudoku Championship, 2025 came to an end! This was followed by a fun event organised by Priyam, cake cutting for Kumaresan sir and bidding good bye to everyone. Looking forward to the next year's ISPC (hopefully I participate in IPC as well next year :))

Indian Sudoku Championship, 2022

I'm happy to share that last weekend I participated and finished at 13th place in the Indian Sudoku Championship (ISC) organised by Logic Masters India.

While this rank is way below my personal best of 7th position at ISC, I'm really happy that I participated after so long.

From 2015 to 2017, I was very regular at sudoku championships and used to participate in online as well as offline events every now and then. However, for the past 4 years I've not been able to remain much active in sudoku due to personal and professional commitments. While I was occupied elsewhere I always wanted to come back to my hobby! And this year I finally did so. I'm happy that I participated in all the online qualifier rounds of ISC and finally at the offline finals.

The next step is definitely to consistently keep participating and improve over the years. And also to make the sudoku blog active again.

It was a wonderful experience participating in the championships and meeting the fellow puzzlers after so long. I would like to thank Logic Masters India, all the organisers, sudoku authors, testers & volunteers for organising such a splendid event. I would also like to congratulate Prasanna Seshadri, Rohan Rao, Kishore Sridharan & Pranav Kamesh for grabbing the top 4 positions.

Below I share the experience of every round of ISC and how it went for me.

With my performance at the online qualifier rounds I started with a base position of 13th rank at the offline finals.

The first round was all Classic Sudokus. 9 sudokus to be solved in 40 minutes. While there are multiple approaches I've used in the past, this time I had decided that in every round I'll start with the middle difficulty sudokus, progress to higher difficulty ones and then come to the easier ones at the end when last few minutes are left. I started the round with the 5th sudoku, was able to solve 5th, 6th & 7th sudoku but broke (made mistake) in the 8th one. I decided to move to the next one instead of fixing it. But again the 9th one was an 80-pointer and I got stuck in it. So, I started solving the 3rd sudoku. I had to make a guess in the 3rd one but finished 3rd & 4th sudoku and later moved to 2nd one. Struggling in the last few seconds I finished 2nd one as well only to realize later that in the last minute hassle I placed an 8 instead of a 9 in the last cell!

The 2nd round had 9 sudokus (1 classic & 8 variants) to be solved in 55 minutes. I started the round with 85-pointer Thermo sudoku, finished it. Then finished Odd Even Sudoku, Battenburg + Killer Sudoku (my personal favourite from the round), Outside Sudoku & Arrow sudoku (yet another fantastic sudoku). In the last few minutes I moved to Classic sudoku. It was a low pointer but somehow I got stuck in it and couldn't complete it. However, I was happy with my performance in this round.

But when the results came out, I found that I had made last cell mistakes in 2 sudokus and lost 145 points because of them. This is one of the most common mistakes which you will find almost all the participants make in at least one sudoku in such championships. But this was a major set back for me as I was down at 18th position now from the 13th position.

The 3rd round had some unfamiliar variants -- 10 of them to be finished in 65 minutes. I could solve 5 of them, was solving the 6th one but couldn't do so within time. Yet again I made a last cell mistake in an 85-pointer sudoku and I was still at 18th position after this round as well. At this point I was gravely disappointed with the mistakes I was making. I had just one round left to rise in ranks.

The final round had 10 sudokus which were connected with each other forming a Pyramid Scheme. I gave my best at the round. I was able to finish the tough ones but got stuck in 25-pointer easy Classic. I took a lot of time to solve it but couldn't move forward as the other sudokus were dependent upon this one. Fortunately I finished 7 out of 10 sudokus in this round and finished at 13th position.

Looking forward to more such championships!