The paper presents the tenth chapter of 'Tabulatura muzyki abo zaprawa muzykalna' ('The tablature of music or musical practice'), which is a handbook of music, the first one written in Polish by Jan Alexander Gorczyn, a well-known polish bookseller, printer, engraver and author of several works on various subjects. The book appeared in print in Cracow in 1647. It had been adressed to beginners in studying music. It consists of ten chapters, in which the author explains fundamental elements of learning music, rudiments of mensural notation, informations about the range of respective voices, the keys, the metrical problems (tactus, the metric values, breaks, triples, proportions), explains how to transfer the mensural into tablature notation. What is most interesting, Gorczyn recommends studying all the theory on the keyboard of the clavichord, and he ends his book with tables for fingerings of basic intervalls and chords on the keyboard, giving thus a concise lesson of application the fingers to the keys. He also provides a reader with fingerings for written-out ornaments for both hands and the unique, althought quite laconic instruction for stringing and tuning of the clavichord. All the problems are taken into analyse in the article. The authoress gives a hypotethical reconstruction of the fretting and is trying to specify the tuning system described by Gorczyn.