I'm having fun and games trying to get round a piece chock-full of difficult forked fingerings at speed. My teacher gave me a tip from Piers Adams - give the note which is giving difficulty a tiny, tiny bit more time than its neighbours when practising. The piece in question cannot be done with alternatives without compromising tone, so I've had no option but to get these tricky fingerings right. In the process of trying out the "lean on it" approach, I've also discovered that making sure the note before the tricky one is absolutely secure and unrushed helps enormously. I must be sooo thick, not to have thought of that before - I hadn't been able to work out why I could do the combinations of notes some times but not at other times.
Anyone else got any tips for this problem?

My teacher always says LOOK at the music. If you consciously look at each note in turn is you play them, however fast, it sometimes helps... but then, sometimes it doesn't!

I'm one of those non-memorisers, so have to do that, but you're right, that does help too.

I don't think that anything is better than a lot of donkey work doing slow practice on difficult passages. They will be patterned into the brain eventually, and then one can increase the tempo. I have a theory that if a passage is played incorrectly more that perhaps a couple of times then a part of one's brain thinks that that is the correct way to do it and tries to reproduce it whenever it can. If the mistakes are never put there it cannot do this. Slow, correct and accurate playing works for me. Then I can play as fast al I need to with little effort.

I agree. In one of his books, Barry Green says how a pro musician (possibly a violin soloist, can't remember) once told him that s/he practises entire concertos at half speed precisely so the notes and rhythms are played correctly from the very beginning. I thought this made a lot of sense.

Will carry on doing that too. Must just be a very slow learner.
Must also try to take own advice about chilling out.

What piece is it?

Jakob van Eyck, Philis schoone Harderinne. I've tried the alternatives I know, and can't get the notes to be equally powerful, and they need to be. Even Marion Verbruggen has a single, barely noticeable fluff in her recording of it, but mine are more obvious - and unpredictable, too. I've been trying to work out what it is which goes wrong sometimes but not all the time.

Fingering can take practice. I use forked fingerings (F, Bb, etc) comfortably because I pronounce my fingering changes to learn. Even now I over-exaggerate my finger movements because I'm a trained classical guitarist and consider my fingers dancing. By feeling and remembering my fingers I learn what to do without thinking. Also, spend time going up and down scale in front of the TV to get it into your automatic memory, rather than just trying to remember as you go. Get it so you can finger any note without thinking time. Then you can read by sight and play as well.

S.