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.

Rules:

Akari:

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.

Shakashaka:

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.

Heyawake:

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

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  P517

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  P518

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  P519

Puzzle No. 513: Shakashaka

Lets start with an unrelated self-plug – https://www.gmpuzzles.com/blog/2021/08/japanese-sums-by-prasanna-seshadri/ Check this out!

Now to today’s puzzle. This is a “fresh” puzzle, i.e. only 2 or 3 people have seen it before.

Rules – Shade a right triangle in some empty cells, each of which occupies exactly half the cell it’s in. Each unshaded area must be rectangular in shape. A number in a cell represents how many of the (up to) four cells orthogonally adjacent to the clue contain triangles.

Penpa link to solve: https://git.io/JRCdn (Click+drag slightly to a corner to draw in that corner’s triangle, just click for dot)

Puzzle No. 472, 473 : Shakashaka, Fillomino

Heh. Will get back to Tuesday-Thursday-Sunday from the coming week. Also, my Puzzle posts will be Tuesday and Sunday now, and the Daily League post will be on Thursday. This is to accommodate Richard Stolk on Tuesdays.

Anyway,

Rules – 

P472 – Rules for Shakashaka.

P473 – Rules for Fillomino.

Enjoy!

P472

P473

Puzzle No. 444-447 : Puzzles from the Visa Application office

In addition to my usual puzzle related activities, I have been managing Team India’s visa application submissions. This has been quite a tough process. As part of the process, I have to stand in queue outside the office for 4 and a half hours, and then sit inside for about an hour more. The puzzles below were part of 9 I wrote when sitting in the office. I was obviously exhausted, and this was more of a “oh, I found a pen and paper, lemme just have a little fun to pass the time” kind of activity. Also, with a pen, I couldn’t erase stuff which makes construction infinitely harder, at least for me. So out of the 9, only 2 ended up working when I reproduced them on the computer. 2 others had easy fixes. The other 5 will have to be discarded as I can’t see what I can do to make them work. This hopefully makes up for my inactivity on this as well as next Thursday. Other than the league post on Tuesday, my next post will be a week after this.

Of the 4 puzzles that made the cut, 3 are Tapa related. This is fitting, as the TVC and CTC are nearing their end. I feel fairly certain of a top 10 finish in CTC, and hopefully somewhere thereabouts in TVC too. Generally happy with how I’ve done this year. The 3 puzzles below have a nice mix of a Classic Tapa, a variant that appeared this year, and a variant from the past. The 4th puzzle is a Shakashaka, which is nothing special.

In other news, the “Around the world in 80 Puzzles” Instruction booklet is out! As announced on this blog before, one of the 4 sets is written by me. I’d like to thank Amit Sowani, for test solving each puzzle and providing some good inputs along the way. I thank Ravi Kumar too, for coming up with the name Indian Intrigue which I liked the most out of the possible names. It was a pleasure working with Zoltan Nemeth and the other Hungarian team members too.

Anyway, puzzles!

P444 : Tapa. Rules for Tapa.

Rated : Medium (could be hard).

P445 : Twopa. If both grids are considered together using the following rule, they will each have a unique solution. In each solution, every clue must behave at least a little bit differently. This means, in a multi-digit clue, some of the digits can have the same behavior, but not all.

Rated : Medium.

P446 : Tapa Trimino. Follow regular Tapa rules (above). Additionally, the wall should only be made up of “L” shaped triminoes without overlapping.

Rated : Hard.

P447 : Shakashaka. Rules for Shakashaka.

Rated : Easy. 

P444

P445

P446

P447

Puzzle No. 382-396 : Czech Puzzle Championship Puzzles

I think this was a set I wrote when I wasn’t that well. That’s not meant as an excuse, but as a warning – I tend to make things harder when I’m ill. However, some of these are also rejects from newspaper bunches for being not-too-easy (Heyawake for example) which means there’s some easy in there too. Unlike my previous puzzle set posts, I decided to find out a bit more this time, which basically means that I can add the points that were assigned to each puzzle. The Skyscrapers Pentomino was not used, but since it was not used for being too hard, I’ve simply valued it at points higher than any of the others.

The Championship had 5 rounds and then a playoff at the end. The first round had the largest time slot and so two of the hardest puzzles of my set, the Yajisan Kazusan and the Shakashaka were moved into that round. Two others, Heyawake and Multiplicative Corral were moved to the Playoff/Final. There’s no point valuing for these, but I’d put their difficulty around the LITS or the Country Road, something of a medium difficulty.

There were 25 participants, and Jan Novotný emerged as the winner, mainly by having a good playoff, as Matej Uher was ahead after the first 5 rounds (377.8 – 299.2). In fact, Jan was 4th before the playoffs, behind Jana Vodičková (332.5) and Jakub Hrazdira (306). Congrats to him, and the other qualifiers. For my round (the 4th round, valued at 110 points), the top scorers were Matej Uher (85), Jakub Ondroušek (77) and Jakub Hrazdira (62). I’m posting only my own puzzles but as a test solver for the event in general, I did have access to the other puzzles too, and the quality is quite high throughout. If you’re interested in knowing more, or you are a Czech/Slovakian interested in becoming a member of the HALAS Association (where I think you will gain access to all these puzzles), I’d suggest you contact Jiří Hrdina, who co-ordinated/organized this Championship.

Rules/links and points –

P382 : Bosnian Road (8 points).

P383 : Country Road (12 points).

P384 : Easy As Tapa (14 points) – Follow regular Tapa rules. Clues outside must be placed in the first unshaded cell in that row or column.

P385 : Fillomino (7 points).

P386 : Heyawake (Playoff puzzle).

P387 : LITS (12 points).

P388 : Masyu [Alternative] (4 points) – Follow regular Masyu rules. Additionally, the loop cannot pass two circles of the same colour continuously.

P389 : Multiplicative Corral (Playoff Puzzle) – Draw a single closed loop along the grid lines that contains all the numbered squares and does not touch itself, not even at a point. Each given number is the product of two numbers: the number of interior squares that are directly in line vertically with that number’s square (including the square itself) times the number of interior squares that are directly in line horizontally with that number’s square (again, including that square itself).

P390 : Nanro (14 points).

P391 : Norinori (5 points).

P392 : Product Heyawacky (25 points). Follow regular Heyawacky rules. Additionally, the number at the top left of a cage is the product of shaded cells in each different region, only pertaining to its area within the cage.

P393 : Shakashaka (40 points).

P394 : Skyscraper Pentomino (60 points?). (Edit – It should be noted that the puzzle in the link has “X” marks where pentominos can’t be placed, whereas the puzzle below has black cells denoting that)

P395 : Sum Skyscraper (9 points). Follow regular Skyscrapers rules. This skyscraper uses the digits 1~7. The numbers outside indicate the sum of the visible digits.

P396 : Yajisan Kazusan (40 points).

Now, the puzzles! Enjoy!

P382

P383

P384

P385

P386

P387

P388

P389

P390

P391

P392

P393

P394

P395

P396

Puzzle No. 351 – 366 : Zagreb Open puzzles

I managed to somehow squeeze this set out in one day just before my exams started, right in the middle of the hectic submissions time in college. After that, Vladimir managed to squeeze in some time on that day itself to test these puzzles, so many thanks to him for that.

Rules all placed at the start of the post with the puzzles coming later (Trying a new format for posting, simply because its more convenient for me. The puzzle captions should aid you in knowing which rule is for what puzzle, but the ordering is the same as well, so it shouldn’t be much hassle either way.

Rules –

351 – Akari.

352 – Fillomino.

353 – Graffiti Snake.

354 – Heyawake.

355 – Japanese Sums – Place the digits 1-6 in some of the squares, so that no digit is repeated in any row or column. Sums on the outside indicate the sums of consecutive digits in that row or column, in order. Each sum is seperated by at least one empty square.

356 – LITS.

357 – Nanro – Write numbers in some cells of the diagram. All numbers in a region must be equal. The given number in a region denotes how many cells in this region contain a number (at least one). Same numbers must not be orthogonally adjacent across region boundaries. Numbered cells must not cover an area of size 2×2 or larger. All numbered cells must form a single orthogonally continuous area..

358 – Odd Even Skyscraper – In addition to Skyscraper rules linked to below, all outside clues that are shaded are odd. The rest are even. Range 1-6.

359 – Pentopia.

360 – Regional Yajilin.

361 – Shakashaka.

362 – Skyscrapers. Range 1-6.

363 – Tapa.

364 – Tents – Place a tent ortogonally next to each tree so that no two tents touch eachother, not even diagonally. Numbers on the outside indicate the amount of tents that are in that row or column.

365 – Walls Fillomino – Some region borders are given; i.e. the numbers on both sides must be different.

366 – Yajisan Kazusan.

Enjoy!

P351

P352

P353

P354

P355

P356

P357

P358

P359

P360

P361

P362

P363

P364

P365

P366

Puzzle No. 340 : Shakashaka

Firstly, if you haven’t yet, I’d highly recommend solving the wonderful Sudoku set authored by Richard Stolk on LMI, V2V (Variations to Variants), still open for participation over the weekend + Monday as usual.

I have a sudden new found obsession for solving and creating Shakashaka puzzles. I’m not sure how or why it started, but it has. So, I wrote 3 Shakashaka puzzles. Out of those, I decided to keep 2 in reserve for future, as I’m trying to do that a bit these days as it’ll help when there’s a bunch of competitions at once. This is the one I thought would least suit any form of competitive solving, and so this is the one that got the cut. I’m sure that while solving this one the reason for that will be obvious, and it is not related to quality.

As for difficulty, I’d say its on the easy side, but prepare for some tricky moments too as I’m horrible at determining difficulty of genres that I’ve just begun creating.

Anyway,

Rules for Shakashaka.

Enjoy!

P340