Sadao Watanabe did not sign his early work
Watanabe's works from the 1940s to the late 1950's are not signed. Probably due to the influence of Soetsu Yanagi, and the Mingei movement. Yanagi put forward a list of criteria that he believed were the conditions for a beautiful object of folk craft to be born, including that the object should be unsigned. The way of mingei is not the way of self-power nor the way of self-assertion, but it is the way of relying on another power. For Watanabe, who interpreted the Mingei philosophy in the light of biblical faith, it was the way of relying on the grace of God (Masao Takenaka in: Biblical Prints by Sadao Watanabe, p. 27). And in the way of grace, Watanabe initially did not sign his work.
Mary Standlee wrote about the lacking signature in her article A Talent For God (Presbyterian Survey 47, no. 9, september 1957: p. 25):
"He long refused to sign his work, a characteristic which has stirred considerable comment and curious inquiry."
"Religion and art both deal with man's inner reality, and an artist is himself the vehicle of the spirit. The answer to absence of signature on the Watanabe prints was not too surprising afer all: his conversion to Christianity, he believes, had been the greatest factor in his life, and his heart so overflows with humility before God the he can show his reverence only through the unsigned contribution of his talent."
Sadao Watanabe's signatures
Later Watanabe changed his views on the signature matter and from about 1956 on nearly all his prints bear his signature and/or seal. He signed the larger prints on momogami in black or white. His signature is in western writing and sometimes, until the early 1960s, also in kanji. The smaller prints on washi are signed in pencil in western writing and sometimes also in kanji. The posthumous prints on washi have a stamped signature.
Sadao Watanabe's seal
Watanabe's seal consists of the name kanji 禎︀, a variant form of 禎, sada, of his given name 禎雄 sadao. This seal is mainly used on the washi prints.
In 1978 mr. James J. Vehling, who worked as a missionary in Japan, bought some prints from Sadao Watanabe. This is the receipt he received for this purchase. This receipt shows Watanabe's Japanese signature and his personal seal (hanko).
The photo of this receipt was friendly provided by James J. Vehling.