As a pianist of several years, I don't tend to think that chording is a very good idea for fast typing. Certain chord combinations are never very graceful and are a good recipe for tendon strain. We learn to avoid certain fingering because of these hand limitations, and part of the reason we can do that easily is because we are generally moving our hands all over the keyboard. The secret to effective piano playing (to limit strain and tiredness and harm) is honestly the complete opposite of what a lot of computer-keyboard-minimalists seem to be striving for - pianists are supposed to minimize finger movement, and send as much of that movement upstream as possible. Transfer finger to hand, hand to wrist, wrist to arm, arm to body - limit individual finger activity as much as possible for relaxed playing. The idea of minimizing computer keyboard keys for having less keys, and putting more responsibility on agile fingers while freezing the hand in one location, seems exactly backward if the goal is for fast, efficient, fluid strain-free typing.

With stenography, you do transfer much of the "push" to your forearms (and keeping the wrist reasonably still). You just place your fingers in the right position for the keys you want. It's unlike typing where you use the force of your fingers to actuate the keys.

The primary goal of steno though isn't to provide chords - it's to learn a short-hand language enough to reduce whole words or sentences down to a single stroke of the arm - so you can get down much more information with less movement.

Insightful comment, thanks for giving a perspective from a completely different profession. :)

There is however something i need to point out to you: Chording is not for fast typing. In fact, since you must hit multiple keys either sequentially or together, just to produce a single signal to the computer, it is guaranteed to be slower. However chorded keyboards would make it possible to type in restricted situations, such as people who are hospitalized, missing limbs, working on something where the other hand is occupied or where body motions are limited, on the go, or heck, simply while lying back and relaxing; while still maintaining a useful speed.

1023, unless you want it to spew characters when you aren't touching it.

Realistically one would not want to use the combinations requiring many fingers (the variants using nine fingers gives you just ten combinations more).

Using max four fingers per input still gives you 10+10x9/2+10x9x8/6+10x9x8x7/24=385 combinations.

That already exists. The most popular modern variant is plover[1]. However, it might be hard to transition to.

[1] http://plover.stenoknight.com/

Speaking of Plover and chorded keyboards, check out this open source stenotype machine:

http://stenosaurus.com

Chatter on the mailing list makes is sound like it will be coming out in October.

Chording keyboards are mentioned in the first sentence of the post.