Simplify the following text for a Grade 8 native English-speaking person.
Original: According to Will Shortz , the modern Sudoku was most likely designed anonymously by Howard Garns , a 74-year-old retired architect and freelance puzzle constructor from Indiana , and first published in 1979 by Dell Magazines as Number Place ( the earliest known examples of modern Sudoku ) .
Simplified: Sudoku ( also called Number Place or Nanpure ) is a puzzle that is very popular in Japan . It was created in Indianapolis in 1979 by Howard Garns and it appeared in Dell Magazines afterwards .