Sudoku

opoyicentral
Opoyi Central

.

World Sleep Day: Study says power nap boosts cognitive performance

opoyicentral
Opoyi Central

. Tokyo, Japan

Maki Kaji, creator and ‘godfather’ of Sudoku

opoyicentral
Opoyi Central

. Tokyo, Japan

Maki Kaji, Godfather of Sudoku, dies at 69 due to cancer