Sakai trains were made in HO and O gauge by a Tokyo-based manufacturer and sold abroad, particularly in the United States and Australia after World War II. Sakai’s O gauge product bore a curious resemblance to Marx. I have read speculation that Marx once used Sakai as a subcontractor, and Sakai used the tooling to make its own trains rather than returning it to Marx, but there are enough differences that I don’t think that’s the case.
What I do know is that Sakai’s O gauge product was a curious blend of cues from Lionel and Marx and the trains worked pretty well. They’re hard to find today, but not especially valuable since few people know what they are. They turn up on Ebay occasionally.