Identifying ocarina friendly sheet music
Because the ocarina has a limited range it is good to get into the habit of viewing sheet music with this in mind. A single chambered ocarina can play approximately an octave and a fourth. This is roughly 6 lines or 6 spaces of standard music notation. Asian system doubles expand this to about 8 lines or spaces. For the rest of this page I will assume the range of a single chamber.
Technically, the low C on the staff refers to C4 or middle C. On the ocarina, it is common to consider this to be low C. Consequently, alto C ocarinas play an octave higher than written and sopranos two octaves higher. It is fine to transpose music into a different octave. So, when looking at sheet music, look at the range—not the octave it is written in.
If you see any music within the range outlined it will be playable. You should not restrict yourself to music written C to F though as many things can be played if transposed. Take the following snippet for instance: if you scan over the notes you'll see G to B. This is an octave and a 3rd. It will fit on an alto C if transposed down a fifth.
For music in major keys written octave to octave plus a fourth, 6 lines or spaces works regardless of the key. For C Major you have to remember where C is on the staff, but in other keys there is a trick you can use to find the root note: in sharp keys, the key note of the major scale is always the note above the last sharp in the key signature. In flat keys it is 3 scale degrees below the last flat. This is true for both the treble and bass clef.
The same idea also works for the natural, melodic and harmonic minor. In flat minor keys the name of the key is two scale degrees above the last flat. For sharp keys it is one scale degree below the last sharp.
Note that there are exceptions to the 6 lines or spaces rule. This range may vary by plus or minus one semitone depending on the key and notes used. Note that accidentals on the highest or lowest note also affect the range.
To give an example of this catch consider a tune spanning C to F in one sharp: at first glance it appears to fit an ocarina in C. In fact it does not as the highest note is F♯, which is out of range. Technically you could consider this G Major, E Minor or C Lydian depending on the tonal centre. You only need to consider the range though.
The following examples should help to reinforce these ideas. Firstly the Swallowtail Jig. A quick scan over the notes reveals that the tune has a range of G to high B, this is an octave and a third which fits easily. You could transpose it down a fifth to fit on an alto C. Alternately it can be played as written on an ocarina in G. As the F♯ is present on the instrument no accidentals are required.
The next tune, The Girl I Left Behind Me, has a range of D to G which fits fine within the desired range. If you transpose it down a major second it will fit on an alto C in the key of F. One accidental is required to replace B with B♭.
While it has a range of D to G, it resolves to G, thus is in G major. Just because a tune is in a given key, C for example, doesn’t mean that it actually fits on an ocarina in that key. Tunes with the key note in the middle of the range are not uncommon, and such tunes usually need to be played on an ocarina in a different key to get the needed range of notes.
This next one is somewhat odd. It's in D Major with a range of F♯ to high A. It fits but a naive approach transposing it down 6 semitones leaves it in A♭ Major. It can be played much more easily by assuming an ocarina with a sub-hole, transposing down 7 semitones to G.
You should be cautious about playing in keys like A♭ Major, depending on the experience of the musicians around you. When I first started playing the ocarina, I just transposed things to fit without paying much notice to the key. As I developed as a musician and wanted to play with accompaniment, I consequently couldn't find anyone willing to play with me. For this reason, I strongly recommend sticking to common keys so you can more easily play with others.
Note that playing notes with subholes isn't always advisable. Lemmy Brazil's Number 2 also has the same range and will fit using a subhole. Whether this is advisable is debatable as the low F♯ occurs on a strong beat. This note needs to be strong and a subhole may not be adequate. It would work if playing in a group where someone is leading the melody on a different instrument.
Thinking about music like this can be difficult at first but will allow you to broaden your repertoire. As you get some practice you'll be able to spot playable music in unusual keys or ranges at a glance. I find it helps to think about the ocarina key that allows me to play something as written. Thinking of the notes of an ocarina in a different key also makes it easy to transpose at sight.
Just because a piece of music fits within range does not mean that it is practically possible to play it, or that it will work musically. Sometimes, a piece of music was written for an instrument with a certain timbre and simply will not sound right without it. Also, music is often written around the limitations of one instrument. What is easy on one instrument can be very difficult on another. For example, it is quite difficult to play wide leaps on the ocarina, both for ergonomic reasons and because they require a very large change in breath pressure. You will be able to recognise such pieces of music as you gain experience.