Technique1 = I -> ii -> V, then modify the 3rd note of the 'middle of phrase' ii chord to make the ii chord Major. This 3rd note of this chord should be one half step away from the V.
Technique2 = I->iv->V, then modify the 3rd note of this iv chord to make the chord minor. This 3rd note of this chord should be one half step away from the V.
Mozart, Don Giovanni, key of G
In this piece, Mozart does not immediately go I to V back to I. Mozart uses more measures. Mozart uses a measure in between I and V chords, by using technique 1.
Mozart goes from G to A to D then back to G. A is the V->V, 5 of 5, 5 interval from D is A. G->D->A, in circle of fifths.
To go from I to the V, use technique 1. In the Don Giovanni piece, to go from G to a D, along a better harmony, use technique 1. This elongates the music and makes a phrase. A phrase is a building block in classical music. A phrase is the part of classical music, sometimes just 2 or 4 measures, that starts and then also seems to have a conclusion.
Technique 1: G->D->A->G, then modify the 3rd note of this A chord to be AC#E (AMajor). Instead of staying diatonic, ACE (Aminor) chord. C# is the nearest neighbor, slighly lower tone, than D, the V.
Francis S. Key, Star Spangled Banner, key of C
In this piece, Francis Key does not immediately go from I to V, then back to the I for his introduction of his first phrase, in the Star Spangled Banner. Francis Key uses more measures. Francis Key uses technique 2. Francis Key goes from C to Aminor to A Major to G major.
To go from I to the V, use technique 2. To elongate the music and make more harmony, use technique 2.
Technique 2: C->A->G, or s it C->F->G. Not sure why I wrote F chord which is the 4th of C Major key. Then modify the 3rd note of this F chord to be FAbC to make the 4th a minor, Fminor. Instead of staying diatonic, FAC, FMajor, chord.
It seems, from this point of view, using accidentals, sharps and flats, is necessary to create great classical music. It seems, breaking the diatonic system, somehow can make better harmony. I thought staying in Key was always the best rule. Perhaps it is, but when moving music notes along a harmony, this a good brief tool to modify some, or one, middle tones with accidentals.
Assumption: Going from I to V and back to I is a very natural great sounding music flow. Because, on a single tight string, the V of any key is most closely related to the I, by nature of how a string vibrates. Taking a string and putting tension on it. Then doubling this length with same otherwise tension, makes an Octave. Then take another piece of string and make it 1.5 the length of string one. If that's how I remember it correctly, Math has the clearest math when analyzing Octaves and 5th's. In summary, everything is about going from I or going from or to V.
Should the techniques follow from a circle of 5ths, or should they be made simpler?
Technique 1, is really taking the ii chord and making it Major. In key of G, Aminor to AMajor.
Tehcnique 2, is really taking the iii chord and making it minor (or major?). In key of C, Eminor to EMajor. Also, is it Ab or G# in Star Spangled Banner. Is it notated as an accidental on which chord? If it is G#, then I can simplify all these, two rules, on how to modify the chord, by sharping them.
reference:
Form in tonal music: an introduction to analysis, by Green, Douglass M.
Mozart =
https://youtu.be/rda6qVAR0Sg?si=2cNaSjySnxICJj2jVivaldi =
https://youtu.be/IEAUguutobs?si=cpNyuKxTR4627Rq5&t=305
Sections below notated using Finale v27. Finale software is no longer being developed, stopped in 2025. The Steinberg sort of took its place in Aug 2025.
First phrase of Mozart's Don Giovanni minuet.
Here is a technique that uses triads (chords with 3 notes) and inversions and a few 7th chords (chords with 4 notes). C#.
Intro of Star Spangled Banner, by Francis Scott Key.
Here is a technique of using a flat (or sharp), Ab, in the bass note of a chord, and a sharp in the melody, F#.
5 minutes into the Vivaldi no 10, op3 Concerto for 4 Violins (without the violas). It's too complex to figure out what sharp or flat Vivaldi is doing to which chords. Here is a technique that is stronger than just triads and inversions. B#, E#.....etc, G#, D#. in the bass and the melody.

I think Korsakov mentioned using accidentals, as just a general technique that may have been more independent, a more broad use or simply just said, accidentals are just accidentals, nothing more. Not sure if he actually said how to use them. His accidentals section of his book, may have not bothered to organize the teaching it into things like the circle of fifths, and perhaps not paying much attention to chords or notes diatonic to the key. If I remember, reading the book, it may have been his Harmony book. But I do recall a section on accidentals. Accidentals are sharps or flats, that change the note on pitch higher or lower, than what is defined diatonically, in the key. Using accidentals, breaking diatonic rules, I suppose overall, depends on the beginning and ending of the phrase. I suppose it depends on what chord is before it and after it. Which take me back to the very basic of composing. Perhaps it's best to just stream of conscious compose. Unless some people can memorize how things sound. I suppose accidentals are to be used briefly.
Another view of using brief sections of chords outside the key of G.

Philip Glass: Façades
A piece with interesting violins by Philip Glass.
A Secret He Will Take to His Grave, by Murray Gold
Doctor Who, The Name of the Doctor,
thirteenth and final episode of the seventh series, episode released May 2013
Abigail's Silence, Doctor who, Katherine Jenkins and Murray Gold
Anna Magdalena Bach - Petzold Menuet, which is in G Major uses c# in melody briefly. Very similar to Don Giovanni by Mozart. Then there is a similar piece in G minor, Petzold: Minuet No. 2 in G Minor (Formerly Attrib. J.S. Bach as BWV Anh. 115)
This Anime episode, from Mezzo DSA, 2004, seems to be a great example of composition, and, with just one instrument. A composition that tells a story, a hero story. It seems to align exactly with the Anime scene at 8:30 minutes into the episode. A tonal home when she is seen jumping down from the sky. A simple rhythm with just one leap or minor interval jutting out, in the beginning part of this scene. The main character geisha like woman is actually her dream, she's running from something. Then a few more chords change the color, or descend, while keeping the rhythm, when the dogs turn into ninjas. Then a higher register of tones, that lead to some interesting chord changes, that all sounds familiar and fun. Then that tonal home for a second, what sounds like a resolve, to the main key chord, when she appears kicking out of the sky with red boots and a determined mad face.
https://archive.org/details/anime-stuff-three_202111/Mezzo+DSA+-+8+(Dub).mp4 then navigate to the
8th episode of Mezzo. The table of contents to 151 Mezzo DSA - 8.
This is how I imagine, constructing a symphony, if it were a process. If I can get the triads right, maybe some inversions. And keep it very simple. Then it's just a matter of repeating and altering some phrases. Altering by length, adding some accidentals, adding more harmony. More variation, maybe even Retrograde inversion, things like this. Spreading and duplicating, inverting, the chords in other instruments.
This mini piano music from the Anime, also, to me, proves that you have to know theory, or what ever it is called, you have to know intervals and what comes next with each new note change. You need to know the mechanics, what's actually happening when descending tones in succession or ascending, in the shortest possible way. It's like you have to have some system, almost like being able to see colors when you hear certain sounds. Or a baseline system for what is suspense, in the form of tones. For me, I kind of guess. But I don't think you can jam or guess this kind of music out, in this case, with a more clear portrayal. And the film crew would probably not be able to wait 2 months, if they see the composer who is just using guesses to create a succinct flow of music. How did this composer know to pound on these chord changes during the ninjas until the main character appears in the red sky, with an impactful chord. And then definitely a conclusion when the other swordsman appears. An accidental, in Key of C Major, on the ii, on the D to D#, compared to making the the vi, the E 'accidentaled', making E to E#, technically F. While these are both applying the 'accidental technique. They are still not the same thing. Sharping the E must be a slightly different kind of sharping, because of math tone frequencies. It's too long to explain, but frets on a guitar get smaller. So the step from E to F is shorter, I think, than the step from D to D#, in a music that centers around Key of C Major. This is why I presume there is another way to think about music systems, that probably is far simpler than staff and keys and letter scales. We probably need strings and pan flute pipes, and little molecules, maybe even something in 3 dimension. But also, the experts probably can see these concepts, and their
advanced concepts, in the music staff anyways. Or maybe this is wrong, as Claude AI suggests:
D to D# = 1.059463 ratio
G to G# = 1.059463
F to F# = 1.059463 E to F = 1.059463 (diatonic, in this case)
Then why are the frets slightly getting smaller on a guitar from C to D...to E to F, to B? I still cannot grasp that each semitone is the same math movement, per harmony. The rest of this episode has pretty good sound as well. The next dream scene has piano and violin. The next dream scene has percussion and horns and synth. The main character says at the end of the episode, "What good does it do, if you don't remember anything," in regards to a dream company, virtual reality providing a ride/experience where you can somehow live out dreams. Perhaps, if you cannot remember your own music, hear, identify and categorize phrases to a system, if you cannot write music for a specific purpose, then you don't have a mini Bach, Mozart, Beethoven system.

Super Dimension Fortress, Macross 1982, anime episode 30 of 36, Viva Maria. This episode starts with a simple but full symphony sound of music at 2:20. The very beginning of the episode, till 3:40. The fade out under dialogue is also amazing. 1 minute to make a full mini symphony.
https://archive.org/details/Macross-ADV-480i/30.+Viva+Maria.mkv?start=91.1https://viva.pressbooks.pub/openmusictheory/Musical game from a museum. I think this was in Dublin, but could be England.