Cha tree is theaceae family and green tea, black tea and Oolong tea in China are made from this leaves. Their difference depends on degree of fermentation. Green tea is an unfermented tea, Oolong tea is a semi-fermented tea and black tea is a fermented tea.
Cha contains caffeine, catechin and theanine etc. Catechin has effects of anti-bacteria, anti-oxidant, anti-cancer and so on. Catechin is an element of bitterness and theanine is an element of Umami[旨味（うまみ）](delicious taste, this is one of the five tastes). Many products of Cha such as detergent and deodorant, which utilizes its anti-bacterial effect, are made.
There are some kinds of teas in Japan and most of those are green teas. For example, Sen-cha[煎茶（せんちゃ）], Matcha[抹茶（まっちゃ）] and Genmai-cha[玄米茶（げんまいちゃ）], etc.
Sen-cha is a tea which is made from steamed, rubbed, dried tea leaves. When Japanese say simply "Cha" in daily life, it mostly refers to Sen-cha. It is the most popular Cha in Japan.
Matcha is made by Ten-cha[碾茶（てんちゃ）]. Ten-cha is made from leaves of covered tea trees by sun shades for some time. It is for stopping photosynthetic, and in consequence, catechin in leaves decreases and theanine in leaves increases. Therefore, the tea has less bitter and increases Umami.
Matcha is ground Ten-cha into a powder by mill. Matcha is more expensive tea than other teas. That is used in Sadō[茶道（さどう）](tea ceremony). Matcha is served with Wagashi[和菓子（わがし）](Japanese confectionery) in Sadō.
Chawan[茶碗（ちゃわん）](tea cup) for Matcha
and Chasen[茶筅（ちゃせん）](tea whisk made of bamboo)
Genmai-cha is a tea that is mixed Sen-cha and steamed & roasted Genmai[玄米（げんまい）](brown rice). Genmai-cha has a flavor such as nuts.
Hōji-cha[ほうじ茶] is a roasted Sen-cha like coffee. That tea is brown color unlike other teas and has roasted good smell.
In addition, there are some tea not using Cha leaves. Mugi-cha[麦茶（むぎちゃ）] is a roasted barley tea. That has a refreshing flavor and it is suitable as a summer drink. Soba-cha[蕎麦茶（そばちゃ）] is a roasted Soba(buckwheat) tea. It has an unique taste and is often served at Soba noodle restaurant.
Kyūsu[急須（きゅうす）](Japanese tea pot)
Upper: Chawan[茶碗（ちゃわん）](tea cup) for daily use
Below: Chawan for guest
Tea tree likes warm weather. Therefore, production areas of Cha concentrate in warm areas.
The main production areas are as follows;
- Shizuoka Prefecture: Cha is the most representative product in Shizuoka. Especially, Makinohara Plateau[牧之原台地（まきのはらだいち）] is the largest production area in Japan. And Cha from Kawane[川根（かわね）] is known as high-brand tea.
- Sayama[狭山（さやま）], Saitama Prefecture: Sayama is the three best Cha production area with Shizuoka and Uji.
- Uji[宇治（うじ）], Kyoto Prefecture: Uji is a production area of high-quality Cha and especially, that is famous for Matcha.
- Yame[八女（やめ）], Fukuoka Prefecture
- Ureshino[嬉野（うれしの）], Saga Prefecture
- Kagoshima Prefecture: Cha from Chira[知覧（ちらん）] is well-known.
Makinohara tea plantations at Makinohara City, Shizuoka
Tea plantation and Mt. Fuji at Fuji City, Shizuoka
I recommend a book about Cha and Sadō, "The Book of Tea[茶の本（ちゃのほん）]" by Kakuzō(a.k.a. Tenshin) Okakura[岡倉覚三(天心)（おかくらかくぞう(てんしん)）].
Okakura was an official of the Ministry of Education and an art historian in the Meiji period. He wrote "The Book of Tea" in English in 1906. This was written for explaining to western people what Sadō is. In addition, you can understand thought of Japanese about art and beauty in this book.
Left:English & Japanese version Right:English version