Puzzle No. 517-519: Nikoli! (Tribute to Maki Kaji)

I haven’t posted in a while. There are a bunch of reasons for this, including travel and a bad reaction to my first vaccine dose.

Anyway, today’s post is a tribute to Maki Kaji, who passed away last week from cancer. I was going to elaborate on my thoughts more, but honestly this post by Thomas pretty much says exactly what I wanted to, perhaps in a better way.

I got into Nikoli.com pretty late, and just had a year of solving before the online solving portion had to close. I do purchase their books from time to time and I absolutely love the giants series.

Like Thomas, my note of thanks will be for his broader contribution to the puzzle community via Nikoli, influencing me and so many other puzzlers positively.

As a tribute, I have written 3 Nikoli style puzzles, and by that I mean ‘Nikoli style’ – I’ve tried to keep look, difficulty and dimensions as I remember them from Nikoli.com.



  1. Place light bulbs (circles) according to the following rules.
  2. Light bulbs may be placed in any of the white squares, the number in the square shows how many light bulbs are next to it, vertically and horizontally.
  3. Each light bulb illuminates from bulb to black square or outer frame in its row and column.
  4. Every white square must be illuminated and a light bulb can not illuminate another light bulb.


  1. Place black “triangles in squares” (see 2) in the grid under the following rules.
  2. There are four kinds of black triangles you can put in the squares (shown below)
    . You cannot place black triangles in the black squares.
  3. The parts of the grid that remain white (uncovered by black triangles) always form a rectangle or a square.
  4. The numbers indicate how many black triangles are around it, vertically and horizontally.


  1. A rectangle, bordered by bold lines, is called a “room”. Fill in cells under the following rules.
  2. The numbers indicate how many painted cells there are in a room. Rooms with no number may have any number of painted cells.
  3. White cells cannot stretch across more than two rooms in a straight line.
  4. Painted cells cannot be connected horizontally or vertically. White cells must not be separated by painted cells.

Rule credits: https://www.nikoli.co.jp/en/puzzles/index.html

Penpa links

P517: https://git.io/J0aKg

P518: https://git.io/J0aP0

P519: https://git.io/J0a1f


Puzzle No. 420 : Heyawacky

Oh btw, I placed 2nd in the Times Sudoku Championship National finals here in India, with Rishi Puri winning it, Rohan Rao coming in at 3rd and Jaipal Reddy completing the top 4.

There were a few articles covering us, I’ll just post the ones related to the finals – here (Times of India, 1st page of Times Sport)  and here.

The rounds themselves were nicely organized by LMI, with the 1st round being a sprint round of 6x6s (classics and mostly variants), the 2nd round just 9×9 Classics, the 3rd round had 9×9 variants and the 4th round was a piece-placement type mechanical round. It was all great fun, especially since I was competing against 2 of the best Sudoku solvers in the world in Rishi and Rohan. I goofed up bad on the 1st round and so did Rohan (even worse). Rishi was super consistent throughout the 4 rounds. Rohan made up a lot of his deficit in round 2 and a little more in round 3, and I had an excellent round 3, meaning we were all really close come the final round, which didn’t have much separation unless one of us didn’t finish it at all. We all finished, and so there wasn’t much change by that round. In the end, I tied with Rohan, but the 3rd round was prioritized and since that was the round where I excelled, I ranked ahead of him. Rishi was a little further ahead.

So to the puzzle. This Heyawacky has quite a tricky start. After the tricky start, there isn’t a whole lot to it, but still a good flow to the end I think.

Heyawacky rules.

Rated – Medium.