There are fruits, “柚子”, both in Japan and China.

When I was in China, I like it very much. In my hometown, the time around November is the  柚子 season, when is close to The Middle Autumn Festival, the whole family would like to share one 柚子, which is a kind of love shared among the family member.

In Japan, 柚子 is another kind of fruit, even the same name.

The Yuzu originated in China. It was introduced to Japan during the Tang Dynasty(around BC618- BC 907), when was the Asuka period in Japan. In Japan the Yuzu was cultivated, but in China mostly of the Yuzu trees were wild.[1,2]. As the time lapsed, they become different, currently, the Chinese Yuzu is called pomelo.

Different in size

Figure 1 is the Chinese Yuzu and Figure 2 is the Japanese Yuzu. The beer can is the same size.

Fig. 1 The Chinese Yuzu

Fig. 2 The Japanese Yuzu

Difference in usage 

The Japanese Yuzu is wildly used for cuisine. It is a kind of condiment in Japanese food because of its fragrance. And there is “Yuzu tea”, in which the Yuzu is sliced and combined with sugar or honey.

In China, pomelo is almost a kind of fruit[3]. And the pomelo is also wildly for medicine.The Chinese eat the sweet and sour fruit is eaten to fortify the lungs and the spleen. They make various medicaments from the seeds, flowers, mature peel, and slices of young fruit by usually drying them up. It is used in treating cough, swellings, vomiting, indigestion, in removing phlegm and resolving alcohol toxins and hangover. The Malays eat the fruit to treat abdominal pains, oedema and phlegm. The leaves are boiled into a lotion and applied on swellings and ulcers. Pomelo fruit is an excellent source of Vitamin C.

Even it is the same fruit at the beginning, but when the fruits in different area, they will have different shapes and usage as the time flied.

Reference

1. The introduction of Yuzu from Wiki(Japanese) 

2. The introduction of Yuzu(English)

3. Pomelo