A classical sonatina theme – free course

Around 1770 music changes face. Gone are the interwoven lines of the baroque: now people want a clear, singing melody, supported by a discreet accompaniment, with phrases as well proportioned as a palace façade. Haydn, Mozart, Clementi and the young Beethoven wrote sonatinas: little sonatas for students and amateurs. Their language is so transparent that it makes an ideal model for learning to build a phrase.

The fingerprints of the style

Accompanied melody: the right hand sings, the left hand accompanies (this is homophony, as opposed to baroque counterpoint).
The period: a 4-bar antecedent ending in suspense (a half cadence on V), then a 4-bar consequent that starts the same way and closes (a perfect cadence V–I).
The Alberti bass: the broken chord low–high–middle–high (C–G–E–G), which keeps the harmony shimmering without weighing it down.
Slow harmonic rhythm: one or two chords per bar, almost always I, IV, V(7) and their inversions.
Contrasting articulation and dynamics: little two-note slurs ("sighs"), staccatos, forte and piano answering each other.
Highly readable cadences, often with the I6/4 – V7 – I formula.

The model: Mozart, Sonata in C, K. 545

Mozart himself called it "a little sonata for beginners". Here are its first two bars (left-hand register simplified):

M:4/4
L:1/8
Q:1/4=120
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] c4 e2 g2 | B3 c/d/ c4 |]
[V:LH] C,/G,/E,/G,/ C,/G,/E,/G,/ C,/G,/E,/G,/ C,/G,/E,/G,/ | D,/G,/F,/G,/ D,/G,/F,/G,/ C,/G,/E,/G,/ C,/G,/E,/G,/ |]

Everything is there: a C major arpeggio in the right hand, stated like an affirmation; then a more delicate reply (B, a little C–D turn, back to C) adding a small "sigh" of resolution. Underneath, the Alberti bass in sixteenths turns over C major, then over G7 with D in the bass (V6/5 → I). Two chords, two bars: a model of economy.

Building an 8-bar period

Here is an original theme in the same spirit, with an Alberti bass in eighths:

M:4/4
L:1/8
Q:1/4=112
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"c2 e2 g3 e | "G7/B"f2 d2 B3 d | "C"e2 g2 c'2 g2 | "G/B"d6 z2 | "C"c2 e2 g3 e | "F/A"a2 f2 c'3 a | "C/G"g2 e2 "G7"f2 d2 | "C"c6 z2 |]
[V:LH] C,G,E,G, C,G,E,G, | B,,G,D,G, B,,G,F,G, | C,G,E,G, C,G,E,G, | B,,G,D,G, B,,G,D,G, | C,G,E,G, C,G,E,G, | A,,F,C,F, A,,F,C,F, | G,,E,C,E, G,,F,D,F, | C,2 G,,2 C,4 |]

Look at the architecture:

Bars 1–4 (antecedent): a two-bar idea (rising arpeggio, falling reply over G7), a climb to high C, then a stop on D over a G chord: a half cadence, the phrase "asks a question".
Bars 5–8 (consequent): same opening (the listener gets their bearings), but bar 6 takes a new direction (F chord, peak on high C) and bars 7–8 close with C/G – G7 – C: a perfect cadence, the question has been answered.
The Alberti bass follows the inversions (B under G7, A under F): the bass line moves stepwise C–B–C–B–C–A–G–C.

The classical cadence close up

The most "Mozartian" formula of all: a C chord with G in the bass (I6/4) turning into G7, then C. The bass stays on G while the upper voices descend:

M:4/4
L:1/8
Q:1/4=112
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"e2 g2 c'2 e'2 | "C/G"g4 "G7"f4 | "C"e2 c2 c4 |]
[V:LH] C,G,E,G, C,G,E,G, | G,,E,C,E, G,,F,D,F, | C,2 G,,2 C,4 |]

Bar 2: the right hand sings G then F (the seventh of G7); that F "wants" to fall to E, and that is exactly what it does in bar 3. This little tension and release is the most recognisable punctuation of the whole classical style.

The classical golden rule: repeat, then vary. The consequent starts like the antecedent; only its ending changes. Listeners love to recognise something and then be gently surprised. Think "2 + 2 + 4": a 2-bar idea, its 2-bar variant, then 4 bars racing to the cadence.

Common mistakes:

An Alberti bass that sits too low (below C2): it rumbles instead of sparkling. Keep it around C3–G3.
Changing chord on every beat: classical style breathes with one or two chords per bar.
Ending the antecedent on the tonic: no question, so no period.
The seventh of V7 rising: the F of G7 must fall to E.

Beyond the theme: sonatina form

A sonatina then builds on this theme: an exposition (theme 1 in the tonic, a transition, a more lyrical theme 2 in the dominant, a short closing), sometimes a brief development, then the recapitulation where theme 2 returns… in the tonic. For now, focus on the foundation stone: a flawless period.

Your workshop

In the ABC editor, copy the original theme above and listen to it. Find the half cadence (bar 4) and the perfect cadence (bar 8) by ear.
Write your own 8-bar harmonic plan, for example: I – V7 – I – V | I – IV – I6/4 V7 – I.
Compose the antecedent (bars 1–4): a 2-bar idea, its variant, and an arrival on D or B over a G chord.
Compose the consequent: copy bars 1–2, then invent a new ending that rises to a peak (bar 6) and closes on C.
Add the Alberti bass in eighths following your plan, then check in the piano roll that the bass line moves in small steps.
Self-check: sing the melody alone. If it already sounds complete, with a question and an answer, your theme is classical. Bonus challenge: write a second 8-bar theme in G major, gentler and more legato.