I blogged back in March about a book for armchair treasure hunters called Secrets of the Alchemist Dar by Michael Stadther. The book is a follow-up to Stadther’s A Treasure Trove that contained clues to find coins hidden in US state parks redeemable for $1 million of jewels. The new book will lead treasure hunters to $2 million worth of jewels. (We’re told anyone in the world can participate, but it’s unclear what, exactly, that means.)

Secrets of the Alchemist Dar will be released Sept. 26th, but Amazon.com is sponsoring a preliminary treasure hunt to promote the book. Starting today, Amazon.com will be placing 1 clue per week for 9 weeks on its web site. Solving each clue will unlock a piece of a 9-piece puzzle. The first person to solve the puzzle will win a ring worth 10,000. To enter the contest, visit the page for Secrets of the Alchemist Dar. From there, you will find a link to the puzzle and a list of sites where you can find the clues.

So far, it seems like the clues might be really lame. The first can be found on the Amazon.com Jewelry and Watches page and asks you to identify: Number of mouse-clicks to complete 1-click purchase for 1-click eligible items. (You’ll get no help from me on that one.) It remains to be seen if any future clues or the final puzzle pose any real mental challenge.

Through a blog called Random Citations, I came across a New York Times article about an upcoming exhibition of mechanical puzzles at Indiana University.  The exhibition will showcase over 30,000 puzzles from the personal collection of Jerry Slocum an expert on mechanical puzzles.

The article is worth a read and contains a number of fun tidbits.  For example, Chinese puzzle boxes were called “Sunday boxes” in Massachusetts in the early 19th century.  Puzzles provided a major source of sabbath recreation for Puritans who could find no Biblical restrictions against puzzle solving.

I discovered this puzzle created by Leonhard Euler from Switzerland on the Random Good Stuff blog.  The site is in German, but the rules are simple and very similar to sudoku.  Each square has an inner and an outer color.  Each outer color may be used only once in each row and column, likewise each inner color may only be used once in each row or column.  (Though the same color can appear in as both an outer and an inner color in the same row or column.)  Additionally, each color permutation (outer and inner) for each square must be unique.

You might also imagine this puzzle as a two-digit sudoku where each digit must be unique in its row or column and the two digits must form a number that’s unique for the whole puzzle.

Interestingly, there are no starting conditions when playing the puzzle on the site.  The goal seems to be just to come up with a valid configuration.

After the World Sudoku Championship took place last March, I posted a link to the final puzzle.  Now, Cihan Atkay has posted five more puzzles that were used in that competition.  The puzzles represent five different sudoku varieties.  Enjoy!

Thanks to zotmeister for this tip. Puzzle Japan is offering their nikoli style puzzles free for the entire month of July. To play them, go to the login page and enter pj for both the username and password. Puzzles available on the site include sudoku, kakuro, nurikabe, and others. Happy puzzling.

Yes, I’ve been behind lately.  The Puzzle competition for Buy A Friend A Book week is already on day 6.  Fortunately, you can be a late comer and still participate.  There are currently six posted puzzles of six different types: crossword, sudoku, logic, wordsearch, hidden picture, and hangman.