Someway, somehow, I'd let over three years pass since I'd last posted a puzzle here - made particularly an asshole move given that I'd stopped at number 49. I had several things I was wanting to do with this journal around the time of Puzzle 50, and I ended up putting them off... for over three years, apparently. Well, I'm finally getting around to doing them, and so here's their harbinger; the puzzle itself is something of an homage to the way things were here, a final hurrah before pressing forward into the future.
A quick note before I get into the instructions here: despite the dearth of puzzle content here as of late, I never really stopped making puzzles - I just wasn't posting them here. I've had puzzles in the last four United States Puzzle Championships, including a Sudoku variant with no givens whatsoever and no special markings in the grid either (the region shapes alone define a unique solution - I was going for the Ripple Effect effect), which I believe is a world first and is regardless the best puzzle I've yet made. If for some unfortunate reason you missed it, it's in my gallery: Sukazu
And now for something completely opposite: a Sudoku variant with a given in EVERY cell.
A partial given, mind you, but a given nonetheless. As perhaps you've noticed, I've been using my own custom "font" for the numbers in my puzzles, drawing them the same way every time from Puzzle 1 to now. To wit:
There have been a wide variety of comments regarding this. Some love the retro appeal; some find it an eyesore. But the comment that really got to me was noting that the '3' and the '8' are distinguished by only a single pixel, which (especially in a Cross Sums) I agree is a problem. But of course, it also gave me the idea for the puzzle below, so I decided Puzzle 50 would be the five-by-five-pixel swan song, and from there I'd move on to something else - I mean, even Strong Bad upgrades his computer every now and then. As for what to upgrade my graphics to, well - I have an idea in mind, but I'd like to hear what my readers would like to see, so comment away.
There are going to be several other changes here soon as well. For starters, this will be the last puzzle I will be soliciting emailed solutions or providing a prize for. Sucks, I know, but I'm also hoping to make up for this by offering more contests. I should note, however, that I'm still not expecting to have a source of income until next month, so don't hold your breath. (Donations to my PayPal account would accelerate the process and, quite frankly, make me feel very appreciated and happy. Having half a face is still a downer. But I digress.) For this puzzle, however, feel free to email me your answer, and while you're at it, tell me if you own a Nintendo DS or not.
So, without further ado: what lies below is a Sudoku puzzle where I've given you one pixel of each solution digit, with the numbers as drawn above; as usual, each digit (in this case from ZERO to nine - I figured, why should zero be left out of the final 5x5 puzzle?) must appear exactly once in each row, column, and region. Note that the red and green regions are disjoint - those are both still ten-cell regions, the smaller segments connected through cell corners in a checkered pattern - but this doesn't change the rules one bit. [In retrospect, I probably should have used a different pair of colors for those...]
As noted earlier, I have lots of other puzzles already composed that were waiting for this one to come out. Now that it has, expect a steady flow of them to follow - again, my goal is to reach one hundred by the time I'm eligible for the United States presidency. There will be some other varied content as well, the vast majority of it (hopefully...) being creative exploits. So welcome back, glad to be back, and let's have some fun, shall we? - ZM
died July 31, 2006
requiescat in pace
Apparently Nikoli is working on something similar to their previous online puzzle-service, but it will be quite some time, and I doubt it will be quite the same. Puzzle Japan was the portal that brought me my experience with the type of puzzles I've been presenting here in my journal. I would not have the skill I have today in creating and solving puzzles were it not for that website. I feel like I've lost a friend.
Over the next eight days (including today), I'll be presenting eight puzzles - one of each type (sans Japanese crosswords) that Puzzle Japan used to provide. Think of it as a memorial service.
See Puzzle 2 for instructions (as if you're not already sick to death of Sudoku). I hope you'll forgive the non-symmetrical givens, but under the circumstances I think this should be acceptable. You'll likely find this easy, but I plan for this eight-puzzle series to get more challenging as it proceeds. You can email me your solution if you'd like me to verify it, but I will not be offering prizes for any puzzle in this series. - ZM
See Puzzle 2 for instructions to the standard Quadrum Quandary puzzle (if for some reason you've been living in the proverbial cave and haven't solved a Sudoku before). In this variant, chess queens are to be used instead of '9's; none may be attacking each other in the solution.
I'm not the first person to think of doing this, but I do believe I am the first to present it as such. For the curious, there are 144 ways nine non-attacking queens can be arranged in a 9×9 grid without violating 3×3 regional restrictions (19 if rotations and reflections are discounted), so there's plenty of room for making more of these. In fact, up to seven such ways can be used simultaneously, so don't be too surprised if you see Quadruple Queens Quadrum Quandary or Quintuple Queens Quadrum Quandary in the future♥
Note there are no queens among the givens. This was very much intentional; I like to see if people actually read directions. If attempted as a standard Quadrum Quandary, multiple solutions would appear to be possible. Anyone that tells me this puzzle has multiple solutions will be publicly and mercilessly mocked. I also believe that this is the first puzzle of any chess-piece variant, built by anyone, that places no chess pieces among the givens. For the record, enforcing that made this puzzle a bloody nuisance to construct, so I hope you really enjoy it. Or at least get really frustrated at it, in which case we can commiserate each other. Future offerings will likely contain given queens. I might even find a better way of representing them in a monochromatic 5×5 pixel square than with the letter 'Q'. But I doubt that.
As always, feel free to comment on the design here, and emailing me your solution may result in your receiving a prize. Also, don't forget to post your choice for supersize Puzzle 30! - ZM
See Puzzle 2 for instructions. Yes, the regions here are not square; that doesn't change a thing.
I wasn't planning on this: when I read about the new tagging functionality, I quickly went back and tagged all my puzzles as such, so that I and others can have a link that displays only them. I also wanted to throw together another puzzle to celebrate. Looking back, I saw that I've only done one of these so far, and given how popular they are the world over at the moment, I figured I'd make one of these. This is my first experiment with non-rectangular regions, and it was quite enjoyable. Comment about the puzzle here; email me the solution if you find it. - ZM
The left-side grid above is an unsolved puzzle. The grid on the right is the solution to the same puzzle. The rules are very simple. Solving these often isn't.
Each square in the completed puzzle must contain one digit such that each digit used appears exactly once in each row, exactly once in each column, and exactly once in each thicker-bounded region (I've colored them in a checkered pattern to make them stand out more, so you can see what I mean). By convention, the digits from 1 to whatever the side length of the grid is are used, but of course it doesn't really matter. Since 4 wasn't among the givens, I could have used zeroes instead in my answer. But I digress.
This sample is practically trivial to solve, but I'll provide a walkthrough so you can see how I'd approach it. First, there needs to be a 1 in the upper-right region (yellowish), and it can't be in the second row (from the top), since there's a 1 in that row already - so it must be in the first row, to the left of the 3. Looking down, there's a 2 in the third column (from the left), so the 2 in the upper-right region must be below the 3. That leaves the 4 to fill in the last box in that region. Now the second row and third column each have only a single empty cell; both are missing the 3. Adding those in, the upper-left region (bluish) needs 2 and 4, and with the given 2 in the first column, the 2 in the upper-left region will have to be in the second column, placing the 4 in the first. Now the first column has only a single empty cell left, which must be a 1. To finish, note that three each of 1 and 3 have been placed in the puzzle - there's only one of each left. They must go in the rows and columns that haven't gotten them yet, so the cell in the third row and second column must be a 3 and the bottom-right corner a 1. The remaining two cells each get a 4, and the puzzle's finished.
That's easy, right? Indeed it is. The one below, however, is a bloody nuisance. Consider it a gift from me to you. Hopefully, you'll figure out some tricks as you go along. You may need to. I'm feeling generous: you may email me if you get stuck, and I'll give you a hint - but only one, and you have to give me what you've solved so far. In creating the puzzle, I also noted the order in which digits may be added to the puzzle to solve it, so if you tell me where you are I can tell you where you can go next... or what mistake you've made. My email address is on my User Info page. I like email from strangers. I'm collecting an archive of the Japanese spam I've received♥
I've made these sorts of puzzles before, but I had never tried to build one with symmetrical starting digits before, much like those seen in Nikoli publications or at the World Puzzle Championships. It's a lot more appealing that way, and if built right, it doesn't really sacrifice the difficulty any. The number of starting digits given is a good indicator of how tough one of these will be; my 23-digit brainwracker below is definitely high-end. (Dell publications usually offer 30 or more digits, making for very easy and subsequently rather unfulfilling puzzles - and they rarely make them symmetrical.) As always, feel free to email me if you solve it, no matter how long it took you or how many people you figure solved it already. Of course, you are also welcome to post a comment about the puzzle (or my write-up) here, as long as it isn't a hint or solution. - ZM