Originally Posted by dddd

There were indeed quite a few versions of Sachs chain from the late-80's going into the 90's, and their widths could differ slightly.
Many shops back then touted these Sachs chains as being better than Shimano chains on the newer bikes having HG-ramped cassettes, but in all of many cases that I remember, the shifting quality suffered and the service interval on cable adjustments decreased markedly.

An exception to the above would be on any bike having a Suntour Accu-7 drivetrain, since the Accu-7 shifters had quite-generous over-shift movement while shifting to larger cogs, and the "flat-sided" Sachs chain was far less likely to momentarily shift up onto the next-larger cog than you were shifting to (9s-width chain would only later solve that problem entirely).
To be fair to Suntour here, they never recommended using UG-Narrow or similarly-bulged HG chain with their shift levers. But I was running re-spaced 7s HG cassette cogs at the time using Accu-7 Command shifters, so naturally had first tried using Shimano's otherwise-excellent HG chain with that setup.

Many of the Sachs chains had a sort of "master link" that was colored black, and you were supposed to shorten the chain only from the other end. I couldn't visually see any dimensional differences on that special link versus the other links of the chain, but I tried to respect it's presence by not cutting it off. Look for this feature before cutting your new Sachs chain (as I believe that this link was there to assure needed added retention strength when used with ramped HG-style cogs).