Kyokushinkai Kanji
The kanji (Japanese characters) calligraphy, worn universally on the front of the gi, simply means "Kyokushinkai", which is the name given by Sosai Mas Oyama to the karate style he created. It is composed of three characters:Kyoku meaning "Ultimate".
Shin meaning "Truth" or "Reality".
Kai meaning "Society" or "Association".