Lachenal (approximate) dates of manufacture #13708 From: "Guido Bos" [1] Formulas for Concertinas Date: Mon Jan 19 17:02:32 EST 1998 Organization: UUNET Benelux My dear friends, I was very surprised to see some of you trying to use the formula for calculating the age of an English or an Anglo system. It ends up somewhere in the year 2000. Therefore, here are the formulas that can be used to calculate approximately the age of your instrument for each system. For the English system: (serial# / 769) + 1850 For the Anglo system: (serial# / 4176) + 1850 For the Duet system: (serial# / 111 ) + 1873 This is a bit of guess work! However, it will give you something to do when you are not practising your music. Maybe a helpfull item to add to the FAQ Chris ? My pleasure, -- Guido