Japan: Why does Mario move from left to right? · Global Voices
Chris Salzberg

Blogger lastline has drawn over 400 bookmarks on the Japanese bookmarking service Hatena for a detailed investigation of the question: Why does the video game character Mario run across the screen from left to right, and not right to left [ja]? The blogger explains that video tends to prioritize movement from right to left, with lead characters on the right and villains on the left; the fact however that early vertical-oriented games had the action button on the right side lead to the development of games in which lead characters move in the opposite direction, from left to right.