learning chess.

Is it beatter to memorise famouse moves or to invent the moves you need as you go?

INVENT 100%

Except for the opening, for which you need to just need to keep from making idiotic mistakes.

A little bit of A and a little bit of B. It is not the famous moves that needs to be remembered, it is the REASON that they were played that's important.

 wise but isent that a lot of B and a lot of C.

Memorizing moves is useless without understanding the reasons for them mate. But i also found ur at a dis-advantage if u dont memorize moves, especially where the openings are concerned. But again understanding the reasons behind the moves are far more important then just memorizing them. I found that out the hard way from OTB games in tournaments....

 I think it's easy to say "invent" -- but where and how exactly does one develop the expertise to invent?  IMO you can't study and learn enough. Study and learn and apply what you've studied.

Memorizing specific lines is useful (and laborious) for the opening, and for certain endgames (try winning with just Queen and King, vs. Rook and King... it's a "theory" win... but just try it against the a full strength computer engine -- it helps to have it memorized!)  -- but not really a critical skill, especiallly at first... but learning certain thematic postions and how to proceed from them... memorizing mating patterns and attacking patterns and how to apply them (flexibly) is a large part of what makes a Grandmaster a Grandmaster.  Working thru full master games (lots of them) and studying the moves is a great way to imprint on your subconscious what good, strong chess looks and feels like.

Only Super GM's have to worry about the rest of the alphabet.

Good luck :)

that might be my problem  I sometimes use plain T.