On the cello, as with all instruments, it is very important that you always know what key you're playing in, and furthermore, what that means for the notes that you will play.
Luckily, there are some very simple methods which allow you to work out finger patterns in all keys.
Obviously, for any of this to work, you need to be very sure of the names of notes. All of this is based around the notes in 1st position, so is only really relevant to those up to about Grade 4/5, but it never hurts to revise!
So step one, just a reminder of the 1st position notes:
Once you're happy with that, we move on to the key signatures.
As anyone who has learned any music theory will know, the order of the sharps and flats within a key signature is fixed.
For the sharps; Father Christmas Gave Dad An Electric Blanket
and for the flats; Blanket Explodes And Dad Gets Cold Feet.
So the first sharp is always F, the second C etc.
On the cello, where key signatures are concerned, the relevant things to note are:
The 2nd and 3rd fingers
Extensions
Where the 2nd and 3rd fingers are concerned, a glance at the table above will show that they share a letter. On the C, E flat and E; on the G, B flat and B; on the D, F and F sharp; and on the A, C and C sharp.
In C Major, we have no sharps or flats, therefore, a glance at the table above will show that we need the 3rd finger on the lower two strings, and the 2nd finger on the upper two strings.
When we add a sharp to make G Major, we now have an F#, therefore a 3rd finger on the D. When we move into D Major with our second sharp, we now need 3rd fingers on all four strings.
The flats work in a similar way. The 1st flat, B, which takes us into F Major, requires a 2nd finger on the G string, and the 2nd, E, for B flat Major, is 2nd finger on the C string.
Therefore, we can show all of this in the following table:
If you're below about a Grade 3 level, this is where you should leave us for now! Come back and re-read this later!
Where extensions are concerned, in some ways it is even simpler. The first flat is B, requiring an extension back on the A string for B flat. The second is E, which requires one on the D string etc.
The first sharp is F, so stretch forward the 4th finger on the C. The second is C, stretching forward on the G etc.
All of that leads to this chart:
Just remember, when you extend, you always need 1x24.