G'day Bald Eagle,

"... Isn't there also a "Duet" system ..." Well, not exactlty ... there are about six - all unique tuning systems, with no relation to each other - or any other instrument!

The first was a Wheatstone Duet System - these have 6 vertical rows of keys ... and expansion on Wheatstone's English system's 4 vertical rows.

Then McCann, a manager at the Wheatstone works shuffled the notes to suit himself and, as he was a good player ... everyone wanted their duet tuned like his! (Looks identical)

Then a designer named Butterworth came up with a very pretty system based on 5 vertical rows. A bloke named Crane introduced it to the Sally Army ... and they started making, or branding their own ... with the Sally brand "Triumph".

The Jeffries family did a strange duet based on spreading the push-pull 'C' row of their Anglo out to 2 rows, now both note each way ... then put semitones in 2 rows outside them. These look like 4-row anglos (and are a rare as hens' teeth).

A bloke named Linton designed his own - 6 vertical rows each hand, but each row is one note of the chromatic scale ascending in octaves. He could play marvellously ... his family were dragooned and accompanied well ... on attaining majority, most of them moved to the other side of the world (mostly Tasmania!).

(Brian?) Hayden has designed a chromatic duet system that works rather like the Continental Chromatic (or 'Chromatica' model) button accordion (or the "free bass" rows on a super-duper piano accordion model with 180 odd basses). I'm not sure of the arrangement ... a little more vertical than the 'Chromatica', I believe.

So take your pick - the best buy would be a McCann Duet, as these are not so popular (spelled 'astronomically priced) and are currently the 'sleeper' of the duet stakes. Fortunately, none of it is my tradition, so I can stick to Anglo (one of the things I bought with the proceeds of selling my 56-key McCann Duet, back in the '70s).

Regards,

Bob Bolton