Jingzu

Jingxiang (敬香 "incense for respect"), shangxiang (上香 "incense on high"), baishen (拜神 "gods worship"), is a ritual of offering incense accompanied by tea and or fruits in Chinese traditional religion. In ancestral religious worship it's jìngzǔ (敬祖 "veneration of the ancestor") or bàizǔ 拜祖 ("worship of the ancestor"). It is observed by a devotee holding joss incense with both hands in front of an altar while praying or meditating. For added respect the devotee or descendent is expected to kneel during and after placing the incense in the urn or at the altar.

Jiangxiang is practiced in diffused Chinese folk religion and also by adherents belonging to the schools of Taoism, Chinese Buddhism and Confucianism. It's used for making a general prayer to one of the Chinese deities, sending well wishes to a deceased ancestor as part of daily prayers in Chinese ancestor veneration, or celebrating the Qingming Festival, Ghost festival and Chongyang Festival .

The number of joss stick varies.

When a devotee uses five, the sticks each represent respect for Tian Di Jun Qin Shi (天地君親師), where tian and di denote the realms of heaven and earth; jun the ruler—which could be Guan Shengdi, the prime minister, or another leader; qin the kins and relatives; and shi one's teacher or teachers.

When offered with three joss sticks, each stand for Tian Di Ren (天地人), again tian and di for the two realms, and ren for the deceased person.

Modern people use one joss-stick out of ignorance and simplificity. Each joss stick should only be used to pay respect for only one entity. It's just like giving one orange to one person. You can't give one orange to 10 people and expect them to be happy.

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Wikipedia