OSS Koi Shirt! OSS Koi on the front in Gray with White Kanji, OSS logo on back. In many cultures, the koi represents perseverance in adversity and strength of purpose. It is said that when caught, Koi often lie still on the chopping board without struggling or flapping around, accepting death honorably. This led to the Koi also being symbols of courage, composure, peace and tranquility under pressure. Needless to say the Koi is the perfect symbol of OSS in the animal kingdom!