See Puzzle 18 for instructions. However, the history of the puzzle I have there is sadly incomplete. Today, I remedy this.
Naoki Inaba is quite possibly the single most underrecognized puzzlesmith alive today. For over a decade, es Puzzle Laboratory has continued to endure and expand, today featuring over 300 different puzzles, most of which are es own original creations. And by "different", I don't mean individual instances - there's over a thousand of those. I mean over 300 unique types of puzzles, making em the most prolific puzzle designer I've ever encountered, and probably the most prolific puzzle designer since Sam Loyd (and given the latter's reputation for plagiarism, maybe even greater than that!). If I may adapt an MST3K invention exchange, e's the Steve Allen of Japanese puzzle design: if you come up with a clever idea you think is new, better check the Naoki-O-Meter to see if e's already thought of that.
Es influence on my own puzzle development and appreciation cannot be understated. Along with Hirofumi Fujiwara - accomplished computer scientist and puzzlesmith in es own right, and the author of the best Sudoku construction tutorial I've ever seen - they are the brains behind Time Intermedia, the company that operated nikoli.com's precursor website Puzzle Japan, which (as I've noted before at the start of my memorial service) was my first true introduction to the depth and beauty of Japanese puzzle design. They are still at work together; their current website, Puzzle GeneRator JaPan (the odd capitalization stems from their URL because they're clever like that), features (among many other things) an extremely fast open-source Sudoku puzzle generator that can be programmed to limit itself to specific human-reasonable deduction techniques and can even handle jigsaw regions and irregular sizes, a series of various beginner-level puzzles of rare designs in PDF form, and the most intimidating book covers ever conceived. But I digress.
Over the years back when I had an office job (yes, I am STILL unemployed - it's tough out there), I would frequently spend downtime at Puzzle Laboratory, clicking some random link to a puzzle, trying to use my limited knowledge of the Japanese language and study of the sample puzzle to deduce the rules, and work through the three or four levels provided in es applets, which always scaled up in difficulty - and cleverness - at just the right pace, exploring the design steadily deeper as they went. It was - and still is! - a fantastic experience and challenge. After I was laid off, I hadn't visited the site for some time, but (especially after cancelling my nikoli.com account) I recently found myself perusing it again, when I discovered something that utterly shocked me:
Some of the puzzles had English instructions!
Sometimes I wondered if I was the only person in the country who knew the site existed. Actually, as I'm typing this right now, I'm still wondering that, although I know that once this is posted, that will change. As well it should. And should have, ages ago. Thankfully, however, as my prompt investigation uncovered, another country managed to build a bridge: Germany. Almost exactly two years ago, members of the German "Logic Masters Forum" took it unto themselves to start deducing/translating the instructions to the puzzles at Puzzle Laboratory, in what has become a grand thread titled Naoki-Projekt. Go thirteen pages in and you'll see the discussion turn multilingual, and sure enough, English translations started popping up as well. And then, as they say, a miracle occurred: Naoki emself heard of the project and joined in, and even asked if e could put the English translations developed so far directly on es site. The answer, of course, was yes. The greatest barrier between es puzzles and the world's enjoyment of them - the language barrier - officially began to break down.
Page 19 of that topic (the current last page as of this writing) revealed a fascinating bit of history. That "NIKOJI" I referenced as how I discovered this puzzle type? Well, NAOKI INABA THOUGHT OF THAT TOO! E'S EVERYWHERE! E'S EVERYWHERE! E'S EVERYW - [ahem] Sorry, what I mean to say is that the design as presented in Puzzle Communication Nikoli is not the original creation - nor by the original creator. The same puzzle design appeared on Puzzle Laboratory first, under the title of Gemini Block (so named because e used each letter exactly twice in each grid, not that the rules required this). As a matter of fact - and this isn't from the forum, but rather my own understanding of the Japanese language - given Nikoli's (and indeed Japan's) penchant for naming things with shortened phrases and that the katakana for 'gemini' actually begins with a 'j' character, I think the title 'NIKOJI' is actually short for "Nikoli's Gemini"... and I thought it was a pompous title before! That's a pretty blatant "borrowing" right there.
Well, I will certainly set the record straight, and it is with great pleasure and honor that I present the following tribute to the true history of To Each Their Own, and indeed to the man who - sometimes unwittingly! - gave me, and very much continues to give me, great inspiration in my humble art.
If you've solved my earlier puzzles of this type, you may find this one surprisingly challenging in comparison. I acquainted myself with Inaba-sensei's own examples of this design in advance of making this puzzle, and I tried to add elements of es style to my own in forging this tribute. I hope you enjoy it. - ZM
EDIT 2011-04-23 3:33 PM EDT: Added link to a Steve-O-Meter video on YouTube (for those poor bastards who didn't get the reference).