I played Go from about 1975 until 1990 and reached 5 dan New Zealand rank (about 6 dan Japanese), and in 1982 I got 8th place in World Amateur Go Championship. Then I stopped playing for 17 years and forgot most of what I knew. I restarted September 2007 and was rated 1 dan on KGS which has now reached 2 dan (early 2012), but a bit higher in Auckland Go Club.
Many years ago when I was smarter I worked out a lot of stuff about ratings and handicap systems and such like.
Two funny go articles written by me in about 1988: