For completeness' sake, some background: Rondo Alla Turca is the 3rd movement from Mozart's famed sonata K. 331, the 1st movement of which might just be one of the most famous variations ever written. Musicians might point to Diabelli to be the most famous, but I feel that many more casuals would recognise the 1st movement theme. In fact, even I can't say I've earnestly listened to Diabelli in its entirety.
Alla Turca is not the most technically demanding piece if you are aiming just to get all the notes right. But just like all other Mozarts, there are few places to hide even your slightest of uneven attacks or notes. The good news is, if you're playing the Alla Turca by itself, chances are you're not playing in front of serious music critics. The bad news is, even for the casuals, this piece is so famous that any wrong note would alarm them much more than the joy they might get from your, say, otherwise otherworldly interpretation.
That out of the way, I do want to point out one passage in the middle section that's trickier than I first thought. This is the passage I'm talking about:
Passage from Alla Turca
To play this passage smoothly without any hint of unevenness requires a lot of attention to the fingering. The entire passage requires a lot of thought:
1st try on Revisit
Blue Arrow: For years I just used my pinky on the B, i.e.: 1-5-4-3 etc on that measure. 1-5 is hard to pull off completely even, and even loses the legato between 1 and the 5. So on my revisit, I first switched to 1-4-3-2, and then 1 on the F#! I.e.: 1-4-3-2-1-4-3-2. Thumb on black key? That's fine. I can pull it off.
Red Arrow: In this measure, I used to go 1-3-4-1-2-3-4-2. The 2 on the C# isn't terrible, but on this revisit, but I changed the fingering to using the thumb on F# in the previous, I decided to try: 1-3-4-2-1-2-3-1. I.e. another 1 on a black key, this time the C#! It's kind of fun actually, and it's not too bad. I liked it for a while.
2nd try on Revisit
Blue Arrow: The Thumbs on Black Keys® is fine, but even 1-4-3-2 isn't good enough for smoothness. So I decided to go with 1-2-1-3-2-4-3-2. Now the "1-2-" part is very smooth, but the "3" on G# when you pass over the 3rd finger isn't as even as 1-4-3-2. So I'm still a bit undecided here.
Red Arrow: Well, my original 1-3-4-1-2-3-4-2 isn't really all the bad. The only difficulty is the F# that comes in the next measure: I've been using 4. It's still ok. So Thumb on C# or 2 on C#? Still undecided.
All these 8 measures just requires a lot of fingering consideration, I just pointed out two fingering problems. Not only do you want smooth and even, you also need to make it sound interesting. So for instance, in Measure 39, if you went with 2-3-4-2 in the last 4 sixteenths in the previous measure, you'll probably be playing 3-4-5-3 here. This is a fingering that works, but harder to phrase because you need exquisite control on your 4th and 5th finger. Not an easy task. So I'm now experimenting Measure 38 with 1-3-4-2-1-2-3-1 so that Measure 39 is 2-3-4-2-1-2-3-1, which is much easier to phrase.
Anyway, just fingering on those 8 measures have taken up an entire post. It goes to show just how much extra thoughts you need to put into fingerings on a Mozart piece since you're completely and utterly exposed.