What is the most technically difficult piece for any given musical instrument (including voice)? Pick an instrument and decide its most difficult piece. I realize much of this is subjective, so we’ll probably get multiple nominations for some instruments. And non-classical pieces are welcome.
My nomination for piano is Balakirev’s Islamey.
I have heard Islamay a few times and it is terrifically difficult, however, it doesn’t seem to go anywhere as a piece of music. Lately I’ve been listening to a lot of Liszt, that stuff is tremendously difficult.
The most difficult piece of music for Tuba! Kraft’s “Encounters II” or Antoniou’s “Six Likes for Solo Tuba.” (Please grant me that my knowledge of tuba litereature pretty much stops in 1988.)
Well, Tool’s Schism is really, really difficult on Guitar Hero. 
:: D & R ::
When I was studying piano, Ravel’s Gaspard de La Nuit was usually held up to be the most difficult in the standard repertoire. It’s so delicate and technical.
Aaron Copland’s Clarinet Concerto is technically difficult, although not too hard for a good play to wrap his or her fingers around (I’ve done it), but it’s damn near impossible to play it well. It was written for Benny Goodman, and I think his performance is still the only one that makes the piece sound musical in addition to demonstrating the technical skill required to play it. Goodman’s performance is here.
Carl Nielsen’s concerto for clarinet is also supposed to be a bear to play, well or otherwise.
I think a lot the contenders for “most difficult” are like this. Yes, a lot of skill and/or talent and/or practice is required just to get the notes out. But the bigger challenge is to do it while making the work sound like a work of art and not just a technical exercise. I’m listening to the recording of *Islamey *linked in the OP, and I can easily imagine it played with no musicality whatsoever, sounding like little more than a lot of very fast picking and crashing around.
ETA: Listening to the Nielsen Clarinet Concerto again, and yeah, I remember why I never even tried to learn my way around it. Way too hard for me.
Cello
Rostropovich himself said that the hardest cello concerto he ever played was Schnittke’s second cello concerto. That’s saying something considering that he premiered over a 100 new works and was one of the greatest cellists in history.
The runners-up would be:
Prokofiev’s Symphony-Concerto (http://en.wikipedia.org/wiki/Symphony-Concerto_%28Prokofiev%29)
Barber’s cello concerto.
Dutilleux’s Tout un Monde Lointain (http://en.wikipedia.org/wiki/Tout_un_monde_lointain…)
As far as solo cello is concerned Kodály’s Sonata for Solo Cello is probably the most difficult in the standard repertoire but there are more obscure works that are much harder.
And for sheer idiocy, I’ll give you Stockhausen’s Helicopter String Quartet (http://www.youtube.com/watch?v=13D1YY_BvWU). Perhaps not the most difficult string quartet but the logistics must be a nightmare. The full version is also on youtube for those of you who might be interested.
For Piano, Liszt is the man. For shear difficulty, his 12 Transcendental Etudes are brutal. Boris Berezovsky does a fine job doing the entire set at one sitting. If you don’t have time for all 12, at least listen to my favorite, #4 (Mazeppa) and #5 (Feux Follets). Of course, Wilde Jagd and Chasse-neige aren’t exactly walks in the park either. Boris does a good Islamey, too, **panache45 **. Overall, I prefer Valentina Lisitsa and Evgeny Kissin as the best contemporary pianists, however.
I heard that the Nielsen is difficult, but the Francaix is damn near impossible.
though in college, I could play the first movement of the Francaix, very slowly.
I am watching this thread, but wouldn’t know where to begin with guitar, the instrument I know best. So many genres of music, and so much is improvised vs. written. Eddie Van Halen does amazing difficult stuff in his leads, but most of them are improvised and not a written structured piece.
Classical - no clue; the stuff I have seen Segovia, Bream, Parkening, etc. play looks beyond tough - no clue how to gauge the “most difficult” piece
Jazz - jeez, no clue. Eddie Lang was doing SUPER complex stuff - he is the guy that brought the archtop guitar up front in jazz combos. Joe Pass was a complete monster - his solo pieces on his Virtuoso series blow my mind.
Rock - well, no clue. I mean, YOU try playing a Ramones song where Johnny is playing a concentrated blast of all downstrokes - in all seriousness, most folks won’t last 30 seconds playing that before their picking hand gives out. It is really, really difficult to do - but also, obviously, bone-headedly simple in terms of major power chords and simple songs. And how do you compare Jimmy Page’s improv vs. Jeff Beck’s whammy bar mastery. I mean, Beck is the obvious answer I suppose - because no one else can do what he does.
Metal - no clue; I hope folks like FoisGrasIsEvil, Snowboarder Bo, ultrafilter and other metal-heads might chime in. Lots of amazing shredding to go around - no clue how to gauge “most difficult”…
Doesn’t even begin to touch flamenco, gypsy, reggae, big band jazz, and, and, and…
And what about violin music? I’d think anything by Paganini, and his First Concerto is notoriously difficult.
I know quite a few trombonists (being one myself) that lament a particular arrangement of Blue Bells of Scotland (I believe the Pryor one) because of the frequent abrupt range switches. I know that trying to play it is frequently seen as a sort of masochistic “challenge run” of sorts.
I don’t think there are many people who can play the bass guitar like Les Claypool.
Well I play the cello, and through my still quite limited repertoire I have found the most difficult pieces to be:
Technically: Elfentanz by Popper ( Popper Dance of the elves "Elfentanz" - YouTube )
This piece is so difficult due to the type of repetitive spiccato bowing in the right hand. Its insanely quick and each note has to bounce of the string, the technique takes months to learn and is entirely different from other bowing techniques or spiccato techniques at slower tempos. It requires a very precise wrist movement at each stroke to induce several bounces per string. In addition the left hand is also very difficult, rapidly moving up and down the string. The run of harmonics very high on the fingerboard is very challenging to get perfect and you cant bluff any notes as a single mistake sticks out.
Musically, a contendor which hasn’t been mentioned already is the Walton cello concerto. Getting the perfect sound for each of the unusual intervals is difficult, and it really sticks out if not played well. This is especially true for the descending double stops and the end of the 1st movement. The second movement on the other hand is extremely rhythmically and technically demanding, a lot more difficult than it sounds. William Walton (1902-1983): Cello Concerto. Full HQ - YouTube
There are a bunch of crazy pieces for guitar. I have no idea where to start, though I suspect that Zappa might have something at the top of the list.
Slee
I don’t know either of those, but I did once hear “Flight of the Bumblebee” performed on a tuba.
As for guitar, I remember a documentary that included Eric Clapton working on mastering Robert Johnson’s licks. So … Robert Johnson?
I think this is a good example of something where the notes themselves are easy for a average skilled musician to play, but difficult to play with the same (or equivalent) almost undefinable “qualities” as the original – the art of the thing, which blends rhythm, pitch, volume, timbre, and more in human ways a machine can’t invent.
Interesting to see this thread. Yeah, I assumed this is about technical difficulty vs. interpretive difficulty.
slee - are you saying the Zappa wrote difficult pieces - I know he used Steve Vai and Adrian Belew for some tough stuff - or that he also performed technically difficult pieces? I think of him as a fine guitarist but not somebody with tippie-top technique.
damianhurst - I am ignorant about cello technique and tough pieces so that was interesting to read. Worth reviving the thread 
Well, there’s the music of Conlon Nancarrow, who wrote pieces for player piano that could not be played by a human, if you want to go there… I would guess that others have done similar things for synthesizers.
I’ll 2nd Liszt for Piano – his hands were enormous, so in addition to the intricacy of many of his works, one has to have long and flexible enough fingers to reach some of his chords and sequences!