I'm not too sure what Mishima was trying to do with this one. Yes, it _is_ the story of a strike, technically speaking...except the strike really doesn't take up that many pages. In fact, it barely takes up any. Society's response to it is outlined sketchily at best, the details of it aren't shown much concern for, and for most of its duration it is located offscreen, out of the writer's focus. The summaries are misleading - the effects of the strike and of unions on Japanese culture are, in fact, never discussed at all. Don't expect a Japanese Germinal here.
The novel works much better as a character study of Komazawa Zenjiro, the owner of the company in which the strike occurs. I'm thinking that must have been Mishima's true purpose, seeing as every chapter title starts with Komazawa's name. Komazawa is a man who lives quite firmly in the past, and tries to adapt the ways of the past to this modern world. (This bears more than a slight parallel to Mishima himself.) His quasi-religious faith in those ways is poignant, and though he clearly has the author's sympathies, Mishima has admirably chosen not to whitewash his faults - Komazawa's hypocrisy, his occasional pointless cruelty and his refusal to even try to understand anything not in the scope of the old ways are all highlighted quite clearly.
However, a good character study does not a good novel make, and the other characters seem, to put it nicely, "unfinished." Otsuki, the strike leader, has precious few appearances to put in for such an important role, and his only motive for what he does, according to the author, is an almost childish chagrin at Komazawa's separation of him from his girlfriend. He seems like more of a plot device than a character. More frustrating, though, is the fact that this novel has many potentially fascinating characters that it simply chooses not to develop. Take the ex-geisha Kikuno, for instance, whose motives are never made anything approaching "clear" - does she love Komazawa? What is the source of her admiration of him? Why did she even want to quit being a geisha in the first place? Or what about the ominous intellectual Okano, who is depicted as a Machiavellian scheming sort of man, but is never given (and never gives) any rationalization for his actions? Did he do what he did solely out of mischief? Was he motivated by financial concerns? What about Komazawa's wife Fusae, who seems to have a (similarly unexplained) martyrdom complex? All these are things Mishima could really have taken some time to flesh out.
As it is, the novel's an often interesting portrait of a very specific type of person, but that's about it. It could have been more. If you're a fan of Mishima, you are of course going to read this, but if this is your first contact with his work, I doubt it will impress you enough to make you delve into the rest of his oeuvre.