Kazuhiro Kotsutsumi was born in Sapporo, Japan in 1979. He started using C/C++ at the age of 14 and proceeded to learn MASM, Delphi, ActionScript, PHP, C#, Perl, and so on.
After working for a web systems development company while enrolled at college, he began programming built-in functions for cell phones.
Having worked as a Project Manager and a freelance programmer for one year, he established his company Xenophy CO., LTD in 2006.
Xenophy has always offered a variety of IT web solutions and has become synonymous with the promotion and expansion of Sencha in Japan.
Currently, Xenophy is a Sencha Reseller and the official Sencha training partner in Japan. In September 2013, Xenophy announced the launch of Sencha Official Training in Japan, a fully localized course with Sencha's official training materials adapted for the Japanese market.
He has already published two Sencha Ext JS guides in Japanese, including Sencha EXT JS 4 – A Practical Developing Guide and he recently co-authored a Sencha Touch guide.