Hey there,
by writing the major scales as a table to practice, I recognized some pattern to it.
For the sharps,
the 4th note of a scale define the next scale sharp note addition.
The 5th note defines the next scale first tone.
For the flats,
The 7th tone defines the next scale flat addition.
And the 4th tone defines the next scales first tone.
For sure Cato is doing is the same thing. But for me it was helpful to write and memorize the table 
I think I’m missing something simple here.
Why is there a 1 above the F on the sharp side? I would read this as saying there is 1 sharp in the key of F which of course is incorrect. So what does the 1 represent?
Hey Colin,
F is included on the # side in Mr Catos diagram, but it is an exception to the rule. The 1 above F represents the one flat ,(Bb), in the key of F.
Cheers, Shane
Thanks Shane 
So you could put 1(b) above that F as a reminder that the 1 represents a flat and not a sharp?
I cant see that this would mess anything up
Hey Colin,
If that makes it clearer, I can’t see a problem. All that matters is that it’s clear to you.
People learn this stuff in various ways. Mr Cato’s trick is one such way to present it.
Cheers, Shane
Great find @KlausGuitar I have written a large topic in the Circle of Fifths that reveals and builds on this idea. The Circle of Fifths - where does it come from, where does it go?
Cheers 
| Richard_close2u | Community Moderator, Official Guide, JustinGuitar Approved Teacher
100% you could do that to help.
Cheers
| Richard_close2u | Community Moderator, Official Guide, JustinGuitar Approved Teacher
I get how the trick works but, I’m with you Flick, I don’t know how to apply it to sharp keys. For example D#
D#, E#, G, G#, A#, B#, D.
So, D# has 5 sharps. How do I get that from Mr Cato’s system? It appears that the key with 5 sharps is B?
There must be some piece of the puzzle that I’m missing.
Hi Phillip,
“In real life”, you’ll need sharp keys very rarely. The sole exception is F# major which has only 1 natural note (B) in it.
From C# major onwards, the cycle starts again and the scale notes will be 1 semitone higher than in their natural counterparts. E.g. the notes of the D# major scale are the same as those of D major, only 1 semitone higher. A double sharp is used when an already sharpened note is raised by another semitone.
Also, you have to have each “letter” only once in a scale, so no G and G# in the same scale or jumps like B#-D.
Hey Phillip,
The key of D#Major has 5 sharps, and 2 double sharps.
Ie.
D#, E#, F##, G#, A#, B#, C##
It is largely a theoretical key, and would not usually be used in practice. Eb Major would be used instead.
Cheers, Shane
I had a very similar realization just this week. How the sharp that get added to make the next scale is always a semitone below the key of that next scale. I was so happy about it that I just needed to make it into a diagram and figure out what was going on. I think it ended up exactly like what you mention.
Thanks for pointing that out Michiel.
@joselp Thanks for the tip. That is better than remembering a mnemonic and faster than my counting out the circle of fifths on my fingers
I had never thought about the cycle of fifths as being sequential for every other letter.
I thought about it some more and saw another interesting fact:
The C D E are the white keys surrounding the 2 black keys on the piano keyboard.
Then the F G A B are the white key surrounding the 3 black keys on the piano keyboard.
With this fact and your tip I can easily remember and write out the 7 notes in the chart.
I also know the open notes on the guitar forward and backwards, so as @apropostt suggested I can think of the 2 thinnest (highest pitch) string barred at the first fret and name the notes going down in pitch for F C G D A E, and remember to add the B.
One other cool thing I noticed about @joselp ’s arrangement of the notes, If you think of the first line as notes on the thickest 6th string (and ignore the F note) and the second line as notes on the 5th string
6th string: F____G____A____B ————->G A B You have the 6 essential notes.
5th string: ___C____D____E ——-———>C D E
Th;is is a great lesson on an easy easy to remember all the sharps and flats of the keys. I wasn’t planning on memorizing the complete major scale table so this will be useful (such as on the Grade 3 test).
Hello @PJPro and welcome to the community.
For awkward keys, which you can figure out on paper but which you will likely not use in practice, there are several approaches.
D# is a key one semitone above D.
List the D major scale:
D major scale → D, E, F#, G, A, B, C#
Rewrite it with all notes raised by a semitone - but, crucially, maintaining the alphabetical list exactly the same.
D# major scale → D#, E#, F##, G#, A#, B#, C##
That is quite ugly isn’t it? Yet it exists in music.
You could do the same going in the opposite (flat) direction.
D major scale → D, E, F#, G, A, B, C#
Db major scale → Db, Eb, F, Gb, Ab, Bb, C
All notes lowered by one semitone.
Alternatively, you could use the circle of fifths which has all keys in all directions both sharp and flat. The Circle of Fifths Part 1 - where does it come from?
I hope that helps.
Cheers
| Richard_close2u | JustinGuitar Official Guide, Approved Teacher & Moderator
Just got to this lesson on the course but slightly confused. I can work out how to get the number of b’s and #'s in a key but not how then to get all the rest of the notes. See the example below:
Hi Stuart,
I usually use the major scale formula (TTSTTTS, see the lesson and the worksheet) plus a few hints, like:
As for the order in which sharps and flats appear, I’d suggest to check out @Richard_close2u’s extra material on the circle of fifths as it’s really well-written and informative, starting with all the basics you need to know. So, in time, you’ll be able to tell things like which major scales may have an A# in them.
@Stuartw it’s easy. Every major scale has 7 notes A B C D E F G.
Using Mr Cato’s chart you know in the key of D major the C and F are sharp. So starting with the root D the note of the D major scale are D E F# G A B C# D.
Using Mr Cato’s chart write out the notes of the A major scale.
It is now!! Went back and had another look at this and it’s a whole lot clearer.
Hi first post so please don’t shoot me down, I find playing the chords in order with C being 0, G being 1, D being 2 , A being 3 etc , really helped me visualise this. I know F is that start point and then I just add in the letter of the chord sharps I’ve already played. The visualisation on the keyboard cracked this in a couple of days for me. Trickier with the flats but play in reverse and add in the next chord. (ignoring the F, as F is always a problem! ) , I hope that helps someone.
