# Interesting facts and quotes about logic puzzles

International Sudoku Day is celebrated on September 9th to honor one of the most popular puzzle games.

The logic of Sudoku is to complete a 9×9 grid by filling each row, column and 3×3 sub-grid with the numbers 1 through 9, where the numbers appear only once.

1. The name Sudoku comes from the Japanese word “suuji wa dokushin ni kagiru” which means “the numbers (or digits) must remain single”.
2. The current version of Sudoku is believed to have originated from the “Number Place” puzzle game published by Dell Puzzle Magazines in the 1970s.
3. The first Sudoku World Championships were held in Italy in 2006.
4. Sudoku is rated from one to five stars; five stars is the hardest. The world’s hardest Sudoku, created in 2012 by Arto Inkala, a mathematician from Finland, is described as level 11, according to The Telegraph newspaper.
5. There are more than 1 billion valid Sudoku puzzles.
6. Although it looks like a math game, Sudoku is a logical game that can be played with numbers, symbols, letters or pictures and it doesn’t require any math skills at all.

Here are some interesting quotes about the game that you might like to read. (Courtesy: quotes sayings, more famous quotes)

1. “I can’t travel without Sudoku.” – Robert Ballard
2. “Who knew we had all this obsessive-compulsive disorder in the world? Well, actually it’s pretty obvious. It explains Sudoku, doesn’t it?” – Bruce Vilanch
3. “The most common concern I hear about learning to code is that people think it requires a lot of math. In fact, most programming doesn’t require any math beyond basic arithmetic. In fact, being a good programmer is not all that different from being good at solving Sudoku puzzles.” – Albert Sweigart
4. “There seem to be two main types of people in the world, crosswords and sudokus.” – Rebecca McKinsey
5. “Crosswords, Sudoku… I’m good at all those things. It’s not everyday but I do stuff on the plane. I love to play chess. It’s my favorite game.” – Larry Fitzgerald
6. “I read each country’s perspective on a topic. I also play a lot of games like bridge, scrabble and sudoku online.” – Indra Nooyi
7. “My secret vice is Sudoku puzzles. I can’t stop playing them. My parents are accountants. I blame them completely.” – Lisa Gardner