This bit needs editing, IMO: "in composed problems, there must be only one correct line of play". I see several issues:

• need to go into a discussion/definition of "correct line of play"
• many problems have more than one line that needs to be analysed
• there is no justification for this assertion
• this assertion, about the validity of the tsumego as a tsumego, is in a section together with other assumptions that are about how to analyse/parse the problem. It shouldn't be grouped with them.

For me it should go in another separate section. It's an interesting topic that merits more analysis. I believe there is some truth to the assertion "a criteria for deciding if a position merits to be considered a good tsumego is that there should only be one correct first move". This is rather different to the current version. I'd be interested on other people's thoughts about this.

I may get round to making some changes to this page myself at some point. can't do it today however.

I've replaced "one correct line of play" with main line. I agree it's pretty ambiguous. In many "black to play" problems, there is no "correct" local reply by white, as in a real game, white would tenuki. But there's still the subjective notion of the "best" reply in terms of testing the solver's understanding of the position. I think this is what the main line page is trying to capture.

Feel free to edit the page some more if you can think of a better way to say it!