This guitar was bought from Old Guitar in Madrid. Surprisingly the commercial advertising is still on Reverb, with all the details that you could expect (even the price!): https://reverb.com/item/20669189-otwin-parlor-guitar-1930-s-solid-woods?locale=fr
It is reproduced below: “Parlor guitar, Otwin brand built in the early years of the 1930s. It has spruce top, sides and back of maple. It has a piece of metal on the bridge that serves to get a better octave of the strings. Take the engraved mark to fire at the top of the top, under the bridge It has a scale of 62 cms and is in very good condition, comfortable to play, functionally sound and with a great sound, strung with silk and steel 0.11 It is a guitar built very finely with a great job, it shows that it was made with great care and love. The founding of the company OTWIN was in 1886 in Schilbach. Franz Otto Windisch was born on 03.01.1866 in Schilbach. His father was the bricklayer Christian Gottlieb Windisch from Schilbach. After his apprenticeship he worked in Markneukirchen at Gläsel & Herwig (Markneukirchen). At the age of 20, he founded a company that was to become a world-class company over the years. In 1903 OTWIN opened a branch in Schöneck. This branch quickly became the main company and, depending on the order situation, it produced 70 – 120 employees, stringed and plucked instruments.”
See “Stefan Lob, Otwin Otto Windisch. Interview mit Herbert Rittinger”, 31 Oct. 2018 / http://www.schlaggitarren.de/home.php?kenn=19&text=hersteller
Some of the Otwin logos, with that of the parlour.