Robert Fuhrer never stopped being a kid. As the founder and president of Chappaqua-based Nextoy, LLC, since 1981, Fuhrer has been in the business of locating and developing new toys and games from Japan and designing them for American consumers.  This past October, Fuhrer introduced his newest venture:  KENKEN, a numbers puzzle that has been touted as highly addictive, fun, and educational. Fuhrer, a Westchester native, and Judy, his wife of 21 years, live in Chappaqua and have two sons, Sam, 17, and Alex, 15, and a daughter, Lara, 12.   

    The son of a Matchbox car salesman, Fuhrer has always had a passion for toys. He had his first toy concept developed at the tender age of 15 — a rocket for Estes called “The Missile Toe.” Upon graduating from Syracuse University, it seemed only natural that he would go into the toy business. After a short stint working on the game “Othello,” he decided that entrepreneurship was his path. So in 1981, with borrowed money and donated office space, he launched Nextoy. Over the years, Fuhrer has co-developed top sellers like Milton Bradley’s “Crocodile Dentist” and Mattel’s “AirBlade.”  In 2004, his iTop was chosen as one of Time Magazine’s “Most Amazing Inventions,” and three other toys were nominated for the Toy Industry Association’s Toy of the Year Awards.

   KENKEN came about in 2006 when Fuhrer made a trip to Tokyo for a meeting with Gakken Company, Ltd, a large educational publisher with a small toy division. Originally created by Japanese educator Tetsuya Miyamoto, KENKEN was used as a teaching method for his students to better understand math while having fun at the same time.  It became “the art of teaching without teaching,” as Fuhrer describes the puzzle that is now credited with placing 80 percent of Miyamoto’s students into elite schools. After the book was published in Japan and sales skyrocketed, Fuhrer decided to bring KENKEN to America. But there was something he had to do first.

   Through a mutual acquaintance, Fuhrer contacted New York Times crossword editor and renowned puzzle master Will Shortz, a Pleasantville resident, to see what he thought of KENKEN. Within 48 hours of receiving his first puzzle, Shortz told Fuhrer that it met every qualification that a puzzle of its kind should, and that he was a convert.

   “That’s when I knew I really had something,” says Fuhrer. Shortz, who has described KENKEN as “the most addictive puzzle since Sudoku,” now endorses the KENKEN books. Last fall, the first four volumes of Will Shortz Presents KENKEN were published (St. Martin’s Press) and within the first month became Barnes and Noble #1 bestsellers.   KENKEN was featured in Reader’s Digest, and United Features Syndicate is incorporating KENKEN into major newspapers including the Boston Globe and the Houston Chronicle. 

   Unlike Sudoku, which is based on logic, KENKEN is based on basic math skills and there is always just one solution. KENKEN puzzles run the gamut from simple to complex. Each “cage,” or outlined group of boxes, within the puzzle has a number. The goal is to decide which number combination adds up to the target number in the cage.  Numbers cannot be repeated in any row or column.  As players learn more and master their skills, they can tackle more complex KENKENs.

   “You don’t even know that you’re learning, but it’s genuinely happening,” says Fuhrer. Each book, which holds 100 puzzles, is under just $10. Free puzzles can also be downloaded from www.kenken.com and www.nytimes.com.  For kids, each puzzle is printed on side-by-side pages so siblings can play along or, if mistakes are made, they can just start over.

   This month, Irwin Toy will be rolling out the first KENKEN handheld device and Nintendo DS is developing KENKEN for its platform. In February, magazines devoted exclusively to KENKEN will be published by Dell Penny Press, a leading puzzle publisher in North America.  Fuhrer is also working on rolling out daily calendars, electronic games for cell phones, and placing KENKEN on Facebook and Twitter.

   “Its ability to cross generations makes it a versatile product,” he says. 

   Fuhrer also hopes that KENKEN will eventually play a larger role in American schools.  Many teachers already use KENKEN in the classroom, including a Harvard professor who is challenging his students, who are math teachers, to develop their own KENKENs. 

   For a major player in the toy business, Fuhrer is down-to-earth and modest about his accomplishments.  And the best part of his job?

   “It’s always an adventure. I get to work with creative people while also being able to develop the business side of toys.  It’s truly a young and innovative way of thinking,” he says.

   For more information about KENKEN, check out www.kenken.com. 

The Fuhrer family, from left, Alex, Judy, Sam, Lara, and Bob