Useishi is the the number 54 in the Okinawan dialect of Japanese. The kata were re-named by Funakoshi to Hotaku, which is Japanese for a woodpecker bird. The idea for the name comes from the pecking motion that is in both of the kata near the end where the performer strikes with the forehead in a snapping, woodpecker reminiscent action. Like Funakoshi's attempts to rename Jiin and Sochin , this name didn't stick and is kept around only as a trivia item. It's too bad the name didn't stick.
Woodpeckers are prettier than numbers.
Matsumura Sokon Gojushiho Dai and Sho are believed to have been created by Matsumura Sokon, the great kata creator and modifier who supposedly grew up with Sakugawa in Tomari City. Matsumura is frequently referred to as Bushi Matsumura, as it was his nick-name. Matsumura Sokon is credited with creating a large number of kata, and some karate historians, if you can call them that, say that Matsumura was the very center of kata creation on Okinawa. There is a legend that Gojushiho was his finest and final creation - intended to be the last kata in his system of Tode. These kata are fairly long, are reasonably difficult enough to spare from intermediate students, and are widely practiced and performed.