The world championship draws the best players from about 40 nations, and The Inquirer is campaigning to host the 2010 contest in Philadelphia. "This appeals to our audience and to us. Our local ownership group loves to have the world's attention on Philadelphia and the whole region," said Inquirer publisher Brian P. Tierney, chief executive officer of Philadelphia Media Holdings, which owns The Inquirer, the Daily News and Philly.com.

Tierney made the announcement yesterday at a news conference at the company's Broad Street headquarters, with Mayor Nutter and puzzle master Will Shortz, who emceed last fall's national competition here and will do so again Oct. 25 at the Convention Center.

The first competition drew more than 1,100 contestants and spectators from 35 states (and one from Canada), and awarded $18,000 in prize money. In addition to the main competitions in easy, intermediate and advanced puzzles, entrants also vied in age categories. The youngest competitor was 6, the oldest, 87. Shortz called it the largest live puzzle tournament ever held in the United States.

"We loved when we saw in the research the broad range of people who enjoy this game," said Tierney, who also laid out details for this year's national contest, which will feature additional Sudoku puzzles and $20,000 in prize money.

It will also feature a special guest: Maki Kaji, president of Nikoli, a major Japanese publisher of puzzles. Kaji is the man who gave Sudoku its name, taking pieces from the bland Japanese title - "Only Single Numbers Allowed." Sudoku actually was born in the United States in 1979, in Dell Pencil Puzzles & Word Games, under the name "Number Place."

Last year's big winner was Thomas Snyder, 27, from Palo Alto, Calif., a postdoctoral student in bioengineering at Stanford University, who pocketed $10,000. He had already won the world championship in Prague, and he captured this year's world title in India.

Sudoku, which employs logic but requires no skill in mathematics, has spread across parts of the world in the past decade, so wildly popular that it became a staple of newspapers here and in Europe within months. It's among a package of six puzzles The Inquirer runs in the daily Magazine section on weekdays and Saturdays.

"We want this championship here in 2010," the mayor said yesterday, "and leading up to that, we're working on some other championships," referring to the city's professional sports franchises, especially the Phillies, currently in first place in the National League East.

Nutter said that Shortz, the New York Times puzzle editor and National Public Radio's puzzler, "added prestige to our efforts." He jokingly entreated Shortz and other New Yorkers to come here for such events and to stay, alluding to the city's declining population. In a conversation with New York Mayor Michael Bloomberg, Nutter said, it was obvious that "he has more than enough New Yorkers, and would be more than happy to send a hundred thousand or so. New York would not even miss them."

Nutter took the podium as six contestants from last year's competition were plowing through a one-star Sudoku - that's the easy category. Jonathan Kustina, 14, of Huntingdon Valley, polished it off in 1 minute, 46 seconds. His grandmother had taught him to play, Kustina said later, "and as soon as I saw it, I just knew I wanted to do it."

Millions are hooked on Sudoku, whose object is to fill in all 81 squares in a grid. (You can play today's puzzle on Page 9 in this section.)

Each row, column and box of nine spaces must contain a digit from one through nine. Puzzles come with 17 to 33 squares already filled with a number, and players finish the game by determining which numbers go in the remaining spaces.

Shortz, considered America's leading puzzle expert, spent part of the afternoon giving tips to residents at Watermark, a retirement community on Logan Square, near 18th Street and the Parkway. "First rule - use a pencil, not a pen!" he told about 45 residents who were attempting the puzzle Kustina had solved so quickly.

Shortz showed how he arrived at filling in a few of the blanks, then went around to check the players' progress. In the back of the room, Ron Abrams, 76, who attacks Inquirer puzzles each day, dispatched the Sudoku with precision and was helping Ella Reiter, 97, who sat beside him.

Reiter does all The Inquirer puzzles except Sudoku, she said. "I know there's got to be something that you follow to do it," she said. "Now I see there is a system."

"It's trial and error," Abrams said. Then, like a renegade: "And I do it with a pen."

Sudoku Championship

The second annual Philadelphia Inquirer Sudoku National Championship will take place Oct. 25 at the Convention Center, 11th and Arch Streets. Registration will begin at 9 a.m., competition at 11 a.m.

Entrance fees. To enter, adult Inquirer subscribers will pay $35; students and seniors (age 65 and over), $15; spectators, $7. Non-subscriber adults will pay $50; students and seniors, $20; and spectators, $10.

Pre-registration. Entrants can pre-register for the championship competition, or for a reception with other Sudoku enthusiasts, from 6 to 9 p.m., Oct. 24, at Independence Seaport Museum. Find details on the championship at www.philly.com/sudoku.