BILL GAITHER/The Register-Mail

You can play sudoku using puzzles printed in newspapers, books, magazines, online and with hand-held electronic games. The Register-Mail's puzzle appears daily in the classified advertising section.

Your number's up

Sudoku provides puzzling pastime

Sunday, July 23, 2006

They come prepared.

Lester brings pencils for everyone; they recently added replacement erasers after grinding down the originals. Miller has a calculator with spellchecker and dictionary on it for other puzzles. They use puzzles from different sources: newspapers, books, handheld electronic games and online puzzles.

The foursome help each other out on the puzzles, and each works the puzzles a different way. Lester plugs in numbers in sequence, from one to nine. Miller usually works across vertical lines in the puzzle, then horizontal lines.

The group has met almost daily at McDonald's, and before that, at Hardee's, for years. They drink coffee, talk about their families and do puzzles: sudoku, crosswords, jumble puzzles.

Sudoku, a numbers puzzle, is probably based on Latin squares, invented by Swiss mathematician Leonhard Euler in the late 1700s. The modern sudoku is a square grid. Players must solve the puzzle by filling in the empty squares of the grid using the numbers 1 through 9 in such a way that no number is repeated in any row, column or 3-by-3 grid. Typically in sudoku books, simple puzzles become progressively more difficult by the end of the book.

Sudoku is not necessarily for "math heads," the women say. But, it's a numbers game that's addictive. And, it's all the rage with publication of puzzles in more and more newspapers, the formation of sudoku clubs, Web sites, chat rooms, competitions, books and magazines.

"I was not going to do them," said Shirley Lester of Galesburg. "I resisted it. Now I'm hooked."

"It's a challenge. I assume it stimulates your brain, at least I hope it does," said Lester.

"Sometimes we get them done, sometimes we don't. We do them together," said Miller.

"It's concentration," said Peer. "It's fun doing it. We laugh a lot."

"The key is patience," Miller said. "Sometimes we redo them on paper napkins until we get it right."

Common sense is key

Jeri Peterson, of rural Roseville, calls her husband Pete a "sudoku-aholic." Ever since last Christmas when their daughter gave him a book of sudoku puzzles, he has completed six or seven books and figured out hundreds of puzzles. He said he spends several hours each day working the puzzles.

The Petersons retired from teaching in Avon schools in 1993. Pete, who taught math, has a system for solving the tricky puzzles.

"You just need common sense," he said. "You have to look at it; you can fill in quite a few just looking at it."

He starts at the right side, working in vertical rows to the left. Then, he goes to the bottom and works horizontally upwards. Then he concentrates on each square.

"I think our brains work in different ways," said Jeri, who sometimes does sudoku puzzles.

"Well, she wants to go square by square," Pete said. "You can't do that. You have to skip around, you've got to look at the whole thing."

Jeri says her husband's patience and the manner in which he paces himself help him with the puzzles.

Pete likens his success in puzzle solving to the way he attacks farm chores.

"If you cut hay all day you're not going to do a very good job of it," he said. "But, if you take four hours to rake it and four hours to bale it, you vary the work. You can do a better job."

About Sudoku

- Modern sudoku puzzles were first published in The (London) Times in 2004, and in 2005 they appeared in American newspapers

- You can play using puzzles printed in newspapers, books, magazines, online and with hand-held electronic games

- Sudoku appears daily in the classified advertising section of The Register-Mail and on our Web site, www.register-mail.com