Citrus. Thought to be a hybrid of the sour mandarin and the Ichang lemon, yuzu is a golf ball–sized fruit with a thick bumpy rind that ranges from green to vibrant yellow depending on ripeness. Origins in China. Sought after for it's unique sour, tart flavour of its' zest

The ultra-tart yuzu is not usually eaten whole but is used as an accent in many traditional Asian dishes. Citrus Information Pages