The back of this instrument was replaced by Hill in the late 1800s. The original back, which Iwasaki still owned in 1978, was a flat back, typical of a viol. Charles Beare, who sold the instrument to Iwasaki, believes that the instrument was originally a 5-string instrument of the viol family.
Ko Iwasaki, Simon Collins, The Strad, April, 1978, London
"The first back manufactured for the instrument consists of two pieces of maple wood characterised by narrow curls which run almost horizontally. A line of purfling decorates the centre joint. The second and 'rounded' back was made around the end of the 18th century [...] The sides match the original back whereas the scroll presents less vivid curls." – Alessandra Barabaschi
Antonius Stradivarius (Volumes I-IV), Jost Thöne, Jan Röhrmann, Alessandra Barabaschi, Jost Thöne, Jan Röhrmann, Alessandra Barabaschi, Antonius Stradivarius (Volumes I-IV), Cologne