is a series of 50 of 'Igo' 'additional', 'supplemental' magazines 別冊 べっさつ (bessatsu). Although the size is bigger yet thinner, lay-out and aim are comparable to the Go Super books which seem to stem from the same era (the '80s?).
Here is an example cover of the volume 'Handicap Ten Commandments': .
Question: who has an index?
I have several issues (books), of which highest number is 42 ('the answer! :-).
Bob McGuigan: The picture shows a book from the series Bessatsu Igo Kurabu of which there are at least 47 volumes (I have No. 47). There is also a Bessatsu Igo series which is separate from the Bessatsu Igo Kurabu series, and, just to confuse things, there is a "NEW Bessatsu Igo Kurabu" series with at least 41 volumes. Takagawa's The Power of the Star Point and Kato's The Chinese Opening, both published by Ishi Press, are translations of Bessatsu Igo Kurabu numbers 5 and 13 respectively. The Go Super Books preceded the Bessatsu Igo Kurabu books.
The "NEW Bessatsu Igo Kurabu" series can be viewed on my blog entry here