1. Coordinate two notes within one hand
Purpose: move two small lines together while retaining control of each voice. Unlike scales separated by a third between the hands, every attack here contains two notes in the same hand. Learn RH and LH separately before combining them.
RH uses 1–3, 2–4, 3–5, 2–4, 1–3. LH uses 5–3, 4–2, 3–1, 4–2, 5–3, with finger pairs read from the lower note upward. The pairs are not identical between hands.
The goal here is connected thirds using changing fingers. First identify each pair and, if necessary, make one detached placement to check simultaneous attacks; then practice connecting two adjacent pairs. Detached repetition is a diagnostic step, not the main exercise. The white notes produce both major and minor thirds: C/E and E/G have different qualities. Keep the fingers close enough to prepare the next pair without stretching the whole hand into a fixed position.
Hear the two lines
Play only the lower line C–D–E–D–C with its printed fingers. Then play only the upper line E–F–G–F–E with its fingers. Restore the pairs and listen for both notes arriving together. Work at a slow quarter-note pulse and connect the adjacent pairs without excessive overlap.
Checkpoint: you can hear and play each line separately, then combine them without one note consistently arriving late or sounding much louder unintentionally.
2. Connect selectively and choose the voice
Begin with two pairs
Practice C/E to D/F alone. Let each voice move toward its next note, using the printed change of fingers. Avoid gripping the first pair until the second has already been struck; excessive overlap blurs the two lines and makes the movement harder.
Then connect D/F to E/G and rehearse the return separately. A comfortable connection across this short fragment does not establish a fingering for a whole double-third scale. Longer routes need planned changes and crossings of their own.
Voice one line deliberately
Play the upper line with a singing sound, then add the lower line softly. Reverse the balance for a second pass. Use a small group and judge the result by ear; a louder upper voice need not mean more force from the whole hand.
If a connection is uncomfortable, use a clear, coordinated release instead. Musical legato can involve articulation and, where stylistically appropriate, pedal; it is not a demand to hold every pair until the next fingers are fully in place.
Where substitution belongs
Changing a finger silently on a held note can sometimes prepare the next interval. It should solve a specific connection in a known passage. Do not insert substitutions into this simple pattern just to make the exercise more complicated. First identify the note that must remain sustained and the next note that needs the freed finger.
Chromatic thirds and extended double-third scales will require separate patterns and fingering review. Chopin’s Op. 25 No. 6 belongs to that advanced repertoire, not to the starting expectations of this page.
Checkpoint: you can choose the prominent voice, retain coordinated attacks on the return, and distinguish a useful connection from a forced stretch.