A tourist visa, issued to aliens who come to china for sightseeing and visiting relatives, is marked with "L" in the many kinds of Chinese visas. Visa L is characterized by a short duration of stay, usually 30 days, no more than 90 days, and could not be extended upon expiration.

Group visa, another kind of tourist visa, is applied by foreigner traveling in tour groups. Group visa is not issued on the passports, but on a separate paper, which requires the group members enter and exit the Chinese border together

From Nov. 15th 2000, aliens traveling to Hong Kong and Macao Special Administrative Regions(SAR) in tour groups organized by travel agencies registered in the above-mentioned SARs are exempted from visa requirements for a period of not exceeding 6 days when entering into the following Chinese mainland cities: Guangzhong, Shenzhen, Zhuhai, Foshan, Dongguan, Zhongshan, Jinangmen, Zhaoqing, Huizhou,etc. The premise is that the traveler shall have the citizenship of a country having diplomatic relations with the People's Republic of China and carrying an ordinary passport

Remark: If you are coming to Lhasa from Kathmandu, you'd better get China visa from Kathmandu because no matter you've already got the visa in your country or not, you must get a visa in Kathmandu, which is regulated in an official memo between China and Nepal.