Mr. Testu [Tetsu-Kun], unconfirmed name, also called Mr. Stamp. I've dated him as 1973, but I've also seen a reference to 1971.
Mr. Tetsu on display after being restored at the Kanagawa Institute of Technology in Japan, 2008.
The author with Mr. Tetsu in November, 2010.
See the full Jiro Aizawa story here 
.