In his Ukraine catalogue, which we all use, John Bulat has a long list of stamps overprinted with single handstamps of Kyiv 2 type. The list starts at # 257 and ends at # 581. That's a lot of stamps. Pity that no one collects them.
In notes in the text, Bulat says that on kopeck values sub-types bb, ee, f, g, gg are stand-alone single handstamps in the sense that we only need a single stamp to classify it as having come from a single handstamp. In other words, bb,ee,f,g, gg are never to be found in the standard a- b - c - d - e five-cliche handstamp.
But sub-types a, b, c, d can only be identified as from single handstamps if they occur in pairs or in right or left marginal positions (b,c,d) or in pairs or right marginal position (a).
Got it? Fine? Now I am going to spoil your day ...
Consider the two strips of five below. Click on the Image to magnify if you think it will help: