Sudoku 102: Windoku

The rare occasion when I remember I have a blog to post to😜

Rules: Apply Classic Sudoku rules. Additionally, each marked 3x3 region contains each digit from 1 to 9.

Links:

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Solution

Sudoku 101: Encaged 4 Sudoku

Sudoku GP Round 4 has started and it features a new variant - Encaged 4 Sudoku. Posting a practice sudoku. 

Given it is one of the mid-pointers in the round I expect the contest sudoku to be easier than this one. Nonetheless, I hope you enjoy solving this sudoku. 

Rules: Apply Classic Sudoku rules. Additionally, the digit 4 may only be orthogonally adjacent to odd numbers. 

Links: 

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Solution

Milestone Sudoku Contest: Winners!

Drumrolls!🎉

A big congratulations to the winners of the Milestone Sudoku Contest!

1st - Aashay Patil (with an impressive timing of 61 minutes!)

2nd - Kishore Sridharan

3rd - Tushar Maheshwari!

Thank you all for participating in the contest. Hope you all enjoyed solving the sudoku :)

If you did not get a chance to solve the sudoku, do give it a try and let me know how you find the sudoku. 

Lastly, once again a big thanks to Nityant Agarwal for test solving the sudoku. 

Sudoku 100: Milestone Sudoku Contest

It's time for the first contest of the blog! You must solve the sudoku and mail an image of the solution to hemantkr97@gmail.com. The first 3 participants to share the correct solution will win Amazon Gift Vouchers! Let's Go!

Rules: Classic Sudoku rules apply. Additionally, some of the boxes have a few decorations. The decorations in each box have been taken from a sudoku posted on the blog earlier (different sudokus for different boxes). The decorations of all forms (line, circle, square, shading, etc.) have been converted to shading. If a box contains decorations, all digits in that box will be exactly same as the sudoku from which the decorations have been taken. It is a part of solving to determine the sudokus from which the decorations have been taken.

Links:

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Milestone Sudoku Contest

It's time for the 100th sudoku and the first contest on the blog!💥

The sudoku (along with the rules) will be posted on the blog at 1 pm IST on 26th July, 2025. The solver has to solve the sudoku and email an image of the solution to hemantkr97@gmail.com. The first 3 solvers who submit the correct solution will win gift vouchers!

A big thanks to Nityant Agarwal for test solving the sudoku. 

Please note that you might require 10-12 sheets to solve the sudoku. A4 sheets should suffice. If there are any questions, please feel free to reach out or comment here. 

Sudoku 99: Little Killer Sudoku

 

Hello! Posting the 99th sudoku on the blog with the theme 99. 

A special announcement - the 100th sudoku on the blog will be a contest! The sudoku will be posted on 26th July at 1 pm IST. The first ones to solve will have the chance to win exciting prizes! Stay tuned for further details!

Rules: Apply Classic Sudoku rules. Additionally, numbers with arrows indicate the sum of the numbers in that direction.

Links:

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Sudoku 98: Edge Difference Sudoku

This Sunday at the Delhi Sudoku & Puzzle Meet up, we solved some sudokus from Japan's World Sudoku Championship selection contest. Out of all the sudokus we solved, I liked the Edge Difference Sudoku the most. This was the first time I was solving this variant. On my way back, I got an idea for an Edge Difference Sudoku I could create. And here it is! Do solve and let me know how you find the sudoku :)

Btw! Something lovely is coming up for the 100th Sudoku (along with chances to win prizes)! Stay tuned! 

Rules: Place a digit from 1 to 9 in each empty cell so that each digit appears exactly once in each row, column and 3x3 outlined box. Digits placed outside the grid represent the difference between the first and the last digits in that row or column.

Links: 

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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 :))

Sudoku 97: Outside 234 Sudoku

 

Rules: Place a digit from 1 to 9 in each empty cell so that each digit appears exactly once in each row, column and 3x3 outlined box. The numbers outside the grid appear in the second, third, or fourth cells of the corresponding row or column when viewed in that direction.

Links: 

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Sudoku 96: Diagonal Sudoku

 

Rules: Place a digit from 1 to 6 each empty cell in the grid so that each digit appears exactly once in each row, column and 2x3 outlined box. Additionally, each diagonal must also contain digits from 1 to 6.

Links:

Online Solving

Sudoku 95: Palindrome Sudoku

In a recent candid conversation on LMI Delhi group, we decided that each one of us will solve a sudoku on 2nd March to celebrate Prasanna's birthday. I don't know if that would actually happen but it definitely gave me an idea for the next sudoku on my blog. Here is a Palindrome Sudoku (PS) with Prasanna's initials - PS - as the theme to celebrate his birthday! :) 

Wishing you a very happy birthday, Prasanna! 

Rules: Classic sudoku rules apply. Additionally, the digits in the cells with lines form palindromes, i.e. they read the same from both the directions. 

Links: 

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Sudoku 94: Disjoint Groups Sudoku

Rules: Classic sudoku rules apply. Additionally, no digit can appear in the same position in different 3x3 boxes.

Links: 

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Sudoku 93: Between Sudoku

 

Rules: Place a digit from 1 to 9 each empty cell in the grid so that each digit appears exactly once in each row, column and 3x3 outlined box. Additionally, every digit on a grey line must have a value which lies between the values of the two digits in the circles at the ends of the line. Digits may repeat along a line. 

Links: 

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Sudoku 92: Position Sums Sudoku

 

Rules: Place a digit from 1 to 9 into each empty cell in the grid so that each digit appears exactly once in each row, column and 3x3 outlined box. Additionally, clues next to the grid give the sum of the first two digits seen from that direction, labelled A and B. Clues in the grey band further outside the grid give the sum of the digits in position A and B for that row or column. 

Links: 

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Sudoku 91: Thermo Sudoku

Rules: Place a digit from 1 to 9 into each empty cell in the grid so that each digit appears exactly once in each row, column and 3x3 outlined box. Additionally, digits along each thermometer are strictly increasing from its bulb to each of its ends.

Links: 

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Sudoku 90: Thermo Sudoku

Hi everyone! We recently finished the first round of Sudoku Mahabharat on Logic Masters India (LMI). I was one of the authors of the round. While creating sudokus for the round, we felt that the overall difficulty of the round was higher than we wanted it to be. So, we made the 9x9 Thermo easier than it originally was, to have a balanced round. 

Posting the original 9x9 Thermo Sudoku. Happy sudokuing!😊

Rules: Place a digit from 1 to 9 into each empty cell in the grid so that each digit appears exactly once in each row, column and 3x3 outlined box. Additionally, digits along each thermometer are strictly increasing from its bulb to each of its ends.

Links:

Solve Online

Sudoku 89: German Whispers Sudoku

Wishing all of you a very Happy New Year with this 23-themed sudoku. 

Rules: Classic Sudoku rules apply. Additionally, adjacent digits along a line must have a difference of 5 or more. 

Links:

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Sudoku 88: Untouch Sudoku

 

Rules: Classic sudoku rules apply. Additionally, identical digits do not touch each other diagonally.

Links:

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Sudoku 87: Thermo Sudoku

 

Rules: Classic Sudoku rules apply. Additionally the digits in the thermometer shapes must be strictly increasing in each cell from the round bulb to the flat end.

Links: 

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Sudoku 86: Fraction Sudoku

Similar to last post, sharing a sudoku which I had created for practice for WSC for the Indian team. This time it is a Fraction Sudoku.

Rules: Put numbers 1/2, 1/3, 2/3, 1/4, 3/4, 1/5, 2/5, 3/5, 4/5 instead of 1-9 so that each number appears exactly once in each row, column and 3x3 outlined box. Letter N means that numbers in neighbouring cells have the same numerator. Letter D means that numbers in neighbouring cells have the same denominator. All possible letters N and D are given.