The Global Tongo Championship is a large tongo tournament on Ferenginar that is held yearly to crown the greatest tongo player in the Ferengi Alliance. There are at least two different divisions, the Golden Masters and the Female Division, the latter of which is held in a sub-basement.
In 2373, Grand Nagus Zek was playing in the tournament but performing very poorly. Ishka, who was playing the female division at the time, began to provide the Nagus with advice. He staged a stunning comeback and won the tournament for the 27th year in a row. From that point he corresponded regularly with Ishka on financial matters and only much later discovered she was a female. When he learned this Zek was initially shocked but soon understood how valuable her advice had been and the two became romantically involved. (DS9: "Ferengi Love Songs")