I don't want to single-handedly introduce categories, when SL doesn't have it in general. But I thought this is useful to maintain certain lists. (Allows mass edits, doesn't show up on the page listed...) This carpenter square thing is more a demonstration than anything. We have a mass of random tsumego, tsumego from games, classical problems which involves certain themes, but aren't reachable when you look for them by topic instead of systematically. Imagine sth. like "double ko problems", if you want to study a topic, such a list might be useful. Like they are the problems on SL are nice to have, but rarely used for study. If you can generate custom sets of problems they might be quite useful. Maintaining lists manually is tedious. I massively edited the endgame problem path etc. and you can still see how far i got.

But it isn't suitable to use it as category in wikipedia style say as "professional", "player from japan", "9 dan", "title winner", "prodigy", "born in 1964", "male".

Best Tapir.

No, in fact it is the same :)

I wasn't aware of the keyword template (although I edited it earlier). Though I believe we have 1) too many keywords already, 2) i just wanted a tool for editors (in this case me), which isn't visible on the outside and which isn't a keyword request. 3) I didn't put the description on the mainpage, as the whole page will be loaded each time the template is used.