Weiqi and Go are the same game. The Chinese name for Go is Weiqi.
Go is the Japanese pronunciation of the Chinese character for the game. The right side element of the character "qi" was originally a hieroglyph of a woven bamboo basket which resembled a game board. The left side element is "tree", signifying "wood". The character for "wei", pronounced "i" in Japanese, means to surround. So we have surrounding game The character for "qi" becomes "gi" in Shogi and the "qi" in Chinese Chess (shangqi). The character for Go shows the right element in "qi" over the character which means "stone". So we have stone and board to describe Go. The more formal name in Japanese is "IGO" which combines the "wei" (surround) character with Go.
The character for Go in Go Seigen's name has nothing to do with the game of Go. In Chinese his name is pronounced "Wu". The Japanese reading for this character is "Go".
Go Seigen is considered one of the three great players in Go history. The others were Honinbo Dosaku and Honinbo Shusaku. You can read about them in "Invincible: The Games of Shusaku".
The above is written in haste. If more clarification is needed, you will find it in the 2000 edition of "The Go Players' Almanac" which I hope to finish by December.
Here are links:
Contact address - please send e-mail to the following address: Sloan@ishipress.com