Transparent blank symbols are provided in each of first, second and third
display plates. The player wins if the same symbols of the first to third display
plates are arranged in line on any of winning lines when the first to third display
plates stop rotating. When the blank symbols of the first to third display plates
are arranged in line on any of winning lines, the sub reel rotates to display the
symbols in motion. Then, the sub reel stops its rotation to display the still symbol.
The symbol on the sub reel is observable through transparent parts in the blank symbols.
