Ing 1996 rules
The Ing 1996 Rules are available here: Ing's SST Laws of Wei-Chi, 1996 (Yuan translation). This is the latest existing version of Ing rules that was also printed in an English version. The Chinese version is available here.
The rules booklet's cover carries the year 1996 and the booklet states that year several times inside. Still in 1997 there was an intention to translate or improve on a translation. Apparently such was not realized and so the 1996 draft with all its editing mistakes made it to the finally printed version.
The booklet was hardly distributed to Western countries. Maybe the first Westerners to see it were those attending the 4th International Go Rules Forum, Beijing, 2005(?).