Sonata

What Sonata is, and how it relates to Cadence

Sonata is built around two strict ergonomic constraints:

1. No lateral inward movement of the index fingers — drop the inner column entirely.
2. Thumbs only move outward, never inward — keyboard layouts often expect the thumb to push laterally toward the keyboard centre, which is biomechanically awkward.

Both constraints proved viable on a 28-key layout, and the design lessons that emerged carried over into Cadence:

In other words: Sonata supplied the design ideas, Cadence's iterative work refined them into a production layout, and Sonata now inherits the refined result back. A clean cycle.

The Family

Cadence and Sonata share the same layer architecture and trigger philosophy. Coda is a separate design exploration with its own layer system. Cadenza is the predecessor that started the family.

The Sonata Base Layer

The 28-key alpha grid, with Home Row Mods on the eight home positions:

Badges show the layer triggered when each key is held. TD = Tap Dance (tap = letter, hold = modifier or layer).

Home Row Mods

Identical to Cadence v1.11.1 — bilateral Meta+Alt is cross-hand, avoiding same-hand HRM conflicts.

The alpha grid was optimised for SFB rate under the no-inner-column constraint. It is not derivable by removing letters from Cadence's grid — several letters are repositioned to columns they don't occupy in Cadence.

Layer triggers — same physical positions as Cadence

The key design decision: layer triggers occupy the same physical positions as in Cadence v1.11.1 — same finger, same row — even though the letter on that position differs. A user proficient with Cadence can move to Sonata hardware without retraining the layer-trigger fingers.

Thumb triggers (1:1 identical to Cadence)

Bilateral letter triggers — same positions, different letters

The trigger position is what matters for muscle memory, not the letter on the key. The same finger doing the same hold motion activates the same layer on either keyboard.

Layer reference — see Cadence

All layer contents (what each key produces while a layer is active) are inherited 1:1 from Cadence v1.11.1. This documentation does not duplicate that information.

For the complete layer reference, see Cadence's documentation:

Cadence's layer contents are designed to leave the inner column (G/M/B/V/J/K positions in Cadence) free of layer content. This is what makes them directly compatible with Sonata's 28-key grid where the inner column doesn't exist physically.

Hardware

Sonata can run on two hardware options:

Why Sonata exists alongside Cadence

If Cadence is the daily driver, what's the point of Sonata?

• Design-research artifact. Sonata is the proof that the constraints (no inner column, thumbs outward only) work in practice. Cadence is the productive realisation; Sonata is the source experiment.
• Migration path for minimalists. Users who reach Cadence and want even less hardware have a documented path: same layers, same trigger fingers, smaller alpha grid.
• Cross-hardware muscle memory. A user can in principle keep Cadence at one workstation and Sonata at another — same layer triggers, same thumb behaviour, only the base alpha differs.

Sonata is not a competitor to Cadence. It's the smaller variant of the same design family.

Versioning

The current release is v0.5.1. Sonata uses a 0.x series during the specification phase. The next major milestone is v1.0, tagged when a dedicated Vial configuration exists.

Versioning policy

v0.5.0 was the initial public release. v0.5.1 (this version) is a documentation update — the Base Layer keyboard visualisation now correctly places the thumb keys (Spc/Tab on the left, Ent/Bsp on the right) below the index columns, matching the physical Ferris Sweep geometry.

From v1.0 onward, documentation will reference two version numbers: the Sonata version (Base Layer state) and the inherited Cadence version (whose layer contents Sonata adopts).