The Global Tongo Championship was a large tongo tournament on Ferenginar that was held yearly to crown the greatest tongo player in the Ferengi Alliance. There were at least two different divisions, the Golden Masters Division and the Female Division, the latter of whose games were held in a sub-basement.
In 2373, Grand Nagus Zek was playing in the Golden Masters division of the tournament, but performing very poorly. Ishka, who was playing in 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. The two subsequently became romantically involved. (DS9: "Ferengi Love Songs")