# Puzzle No. 378 : Arrow Sudoku [Daily League]

Firstly, Mathgrant, someone who I personally have had limited interactions with, but have a lot of respect for as a fellow author in the puzzle community, has fallen into some tough times. If you are feeling generous and want to give back to the puzzle community in some way for all the puzzles you’ve enjoyed solving (and if you’re new to his blog, you’ll find many more there), I suggest reading that post I’ve linked to and seeing whether you can help out. Also, my best wishes to Mathgrant hoping things get back to normal.

Now to today’s post.

If anyone is interested in contributing to the league, just join our facebook group and notify us that you’d like to. Otherwise, you can just join in and solve the rest of the Sudokus by top quality authors, and also discuss techniques and such.

Today’s Sudoku is an Arrow Sudoku. I’ve wondered why Arrow Sudokus generally have many givens whereas Killer Sudokus generally have no givens. I suppose its to do with the fact that digits are more difficult to force into an Arrow Sudoku without crowding arrows and making things messy. In this one, I tried to reduce the givens as much as possible while trying to preserve symmetry and not make the arrows crowd in the grid.

Difficulty wise, like the Yajilin in my previous post, this is probably not particularly hard by WPC standards but I’ll keep the rating anyway. I still think it has a few tricks that’ll make anyone pause and think though.

Rules – Follow regular Sudoku rules. Additionally, the number in a circle is the sum of the digits which are covered by its arrow. For circles with multiple arrows, apply the rule for each arrow separately.

Enjoy!

P378

# Puzzle No. 377 : Yajilin

Been such a long time since I posted a  (Non-regional) Yajilin. You’d have to go all the way back to my Polish set if I’m not mistaken.

Anyway, LMI hosts May Puzzle Test, Deception this weekend. It features some known, some not so common puzzle types with a little deceptive variation. The author is Ivan Koswara, better known as chaotic_iak.

Anyway, the puzzle below has a few places that’ll definitely need you to stop and think.

Rules for Yajilin. The blank gray cells are just clue cells without any numerical indication. The loop cannot pass through them and black cells can be adjacent to them.

Enjoy!

P377

# Puzzle No. 376 : All Even or All Odd Sudoku [Daily League]

Its been a mad, fun, exhausting 2 days. One evening with Manchester United Fan Club Mumbai at a screening of Sir Alex’s last home game in charge and also the trophy presentation. Full of mixed emotions but we made the most of enjoying the occasion. A day later, I was at the Wankhede stadium within shouting distance of the Hyderabad entrance, watching Pollard go on that six hitting spree in the IPL.

Anyway, back to today. You can download the league’s Week 16 PDF and Week 17 PDF.

Today’s Sudoku is pretty easy considering the things that can be done with this variant, but may still be a little challenging for first timers.

Rules - Follow regular Sudoku Rules. Additionally, in each 3×3 box, the shaded cells must be of the same parity, i.e., either they must all contain even digits or they must all contain odd digits.

Enjoy!

P376

# Puzzle No. 375 : Kurotto

Earlier this year, there was a contest on Tawan’s blog called Nikoli Hurdles. There were 8 Nikoli puzzles placed as hurdles for the participants, with the entrants who submitted all answers correctly then participating in an online randomized rock, paper, scissors game. The results of that are here. I received my prize a week ago now I think, and there’s 2 new-ish (I’d seen a few before the book, but not that many) genres on here, both of which I like. One of these is Kurotto. So I thought I’d create a Kurotto for the blog. I’ll let you be the judge of how good it is. On a difficulty scale here, it’d be a medium, but on Nikoli’s difficulty scale I see it being rated with a crying face.

Anyway,

Rules for Kurotto – Shade in some cells in the grid. Circled cells cannot be shaded. The number in a circle is the total number of shaded cells in the shaded cell groups that are orthogonally touching the circled cell. In other words, traveling through only shaded cells orthogonally, the circled cell must be able to reach as many shaded cells as its number indicates. Other instances of this puzzle have cells with blank circles too, which play no part except for being cells that can’t be shaded.

If that wasn’t clear or you want to see an example, here is the Nikoli version of the rules.

Enjoy!

P375

# Puzzle No. 374 : Odd Sudoku with Descriptive Pairs [Daily League]

Week 15 PDF.

Compared to how difficult Descriptive Pairs can usually get, I think the Odd part tames this combination a lot and puts it on the easy side. I still like how it turned out, especially with the clue pairs working out with a “same sum” theme that I was trying.

Rules - Follow regular Sudoku rules. Also, all shaded cells must contain odd digits. Additionally, for every pair of outside clues X and Y, at least one of these cases is true :

1) X is in the Yth position in that direction.

2) Y is in the Xth position in that direction.

Enjoy!

P374

# Puzzle No. 372 : Nurikabe [Windows]

Well, not exactly Windows. I’d made this variant in a slightly more restrictive way earlier which made it too easy, so wanted to use it a bit more this time. I wouldn’t call it difficult as such, there’s one tricky Nurikabe bit, and the rest goes smoothly enough.

Rules – Follow Nurikabe rules. Additionally, the 2 regions need to be negatives of each other. If a cell is determined as island part in one, its corresponding cell in the other region needs to be a stream part, and vice versa (rotations or reflections do not need to be considered).

Enjoy!

P372

# Puzzle No. 371 : Kropki Sudoku [Daily League]

If you’ve not heard yet, LMI has started Beginners’ Puzzle Contests after the success of Beginners’ Sudoku Contests, and the first one is a lovely Classic Masyu Contest!

As I said in my last post, I’ve been busy with the Delhi Brain Games event as well as my exams. My exams got over today, and DBG was held successfully on Sunday. So, I’m looking at a relatively not-so-busy schedule ahead (after today). I’ll try to get back to regular posting here again. There’s also gonna be some more puzzle sets I’ll be posting here on some later date. For now, I’m in a hurry to finish things today that have been pending because of my exams + DBG. So, here’s an easy Kropki for the daily league.

Rules - Follow regular Sudoku rules. Additionally, If the absolute difference between two digits in neighbouring cells equals 1, then they’re separated by a white dot. If the digit in a cell is half of the digit in a neighbouring cell, then they’re separated by a black dot.

Enjoy!

P371

# Puzzle No. 370 : AntiDiagonal + Fortress Sudoku [Daily League]

Daily League PDF – Week 13.

A little announcement – Around a month or so ago, I was contacted by the people of Sportz Consult, a Sports Management Company that is interested in branching out to Intellectual games. The first such competition, Delhi Brain Games will be held in Delhi this Sunday, and a part of this event is the Solvathon (Instruction booklets available on that link, to those of you who are reading this, are new to puzzles in general, and have registered for the games, these booklets are highly descriptive of what you will be challenged with in the actual events). The Solvathon consists of an hour long Sudoku part and an hour long Puzzle part, and they wanted us (me and Rohan Rao) to provide puzzles for the event. We’ve also provided the material for the Mental Math event.

Since I’ve been busy with this, my exams and many other things, I’ve not been able to give time to posting about this earlier. However, I will say to Indian puzzle enthusiasts in general to watch out for more such events organized by Sportz Consult in the future.

Now, back to “business as usual”. Today’s Sudoku is a hybrid. It might be difficult simply based on the hybrid rules coming into play. Both the variants I chose are quite restrictive, but this is one of those where I was particularly adamant to make it work for some reason. In the end it turned out nice enough I think.

Rules - Follow regular Sudoku rules.  Additionally, each of the main diagonals must contain exactly 3 distinct digits. Also, the digits in the shaded cells must be higher than their orthogonal neighbours.

Enjoy!

P370