Monastic Rules Development in China

I have read from the books and articles that monastic rules (vinaya) in China have experienced a few stages of development. Vinayas had changed a few times in China, some Buddhist masters put additional rules or altered the Vinayas.

As we know that Theravada Vinayas are fixed in number and they did not change from the Buddha's time.

Any comments whether the monastic rules can be changed or should not be changed?

with metta,

Brahma Net Sutra Bodhisattva Precepts

This sutra introduces Vairocana and his relationship to Gautama Buddha. It also states ten major precepts for Bodhisattvas, and the 48 minor precepts to follow to advance along the bodhisattva path.

The Bodhisattva precepts of the Brahma Net Sutra came to be treated in China as a higher ethic a monastic would adopt after ordination in addition to the Prātimokṣa Vows. In Japan, the ten precepts came to displace monastic rules almost completely starting with Saicho and the rise of the Tendai.

The name of the sutra derives from the vast net that the god Brahma hangs in his palace and how each jewel in the net reflects the light of every other jewel:
At that time, he [Shakyamuni Buddha] contemplated the wonderful Jewel Net hung in Lord Brahma's palace and preached the Brahma Net Sutra Sutta for the Great Assembly. He said: "The innumerable worlds in the cosmos are like the eyes of the net. Each and every world is different, its variety infinite. So too are the Dharma Doors (methods of cultivation) taught by the Buddhas."

The Brahma Net Sutra has a list of ten major and forty-eight minor rules known as the Bodhisattva Precepts. The Bodhisattva Precepts may be often called the "Brahma Net Precepts", particularly in Buddhist scholarship, although other sets of bodhisattva precepts may be found in other texts as well. Typically, in East Asian Mahayana traditions, only the 10 Major Precepts are considered the Bodhisattva Precepts. According to the sutra, the 10 Major Bodhisattva Precepts are in summary:

Not to kill or encourage others to kill.
Not to steal or encourage others to steal.
Not to engage in licentious acts or encourage others to do so. A monk is expected to abstain from sexual conduct entirely.
Not to use false words and speech, or encourage others to do so.
Not to trade or sell alcoholic beverages or encourage others to do so.
Not to broadcast the misdeeds or faults of the Buddhist assembly, nor encourage others to do so.
Not to praise oneself and speak ill of others, or encourage others to do so.
Not to be stingy, or encourage others to do so.
Not to harbor anger or encourage others to be angry.
Not to speak ill of the Buddha, the Dharma or the Sangha (the Triple Jewels) or encourage others to do so.
Breaking any of these precepts is described as a Parajika offence.

The Bodhisattva Precepts of the Brahma Net Sutra are compulsory to be undertaken and observed by all the monks and nuns of the Chinese Mahayana Buddhism, and which are often held at the Triple Precepts Platform ceremony annually, especially for the new novices of the Chinese Mahayana Buddhism.

Vinaya used in China

When we go along the history of Buddhism, the first episode of different views in Vinaya was stated when Venerable Ananda informed the first council about the Buddha's statement: " if the sangha so desire, the sangha may do away with the lesser and minor rules after the lapse of me". But this was turned down by the first council chaired by Venerable Mahakassapa. Nothing will be change in the Vinaya was adopted by the council and this carried down by Theravada up to today. At about the same time,the episode of elder Purana about the disagreement of the first council where he mentioned that he will have his own set of Buddha's teachings and the Vinaya was preserved by Mahisasakas. The Vinayas present today in Chinese were brought down from the era of Nikaya Buddhism. 5 Vinayas are used in Chinese Buddhism today, they are
1. The Ssu-fen lu of the Dharmaguptaka School
2. The Shih -sung lu of the Sarvativadin School
3. The Wu-fen lu Of the Mahisasaka School
4. The Mo-ho-seng-chi lu of the Mahasanghika School
5. The Ken-pen Shou-i-chieh-yu-pu lu of the Mulasarvastivadin School

With the history of Venerable Ananda about minor rules and the spirit of Mahayana Buddhism in China, a lot of adaptation had been made to foster the growth and penetration of Buddhism in all folks of live in China. New rules had to set to suit the new monastic life in China and a lot of cultural differences had to left behind from the original country. Especially Ch'an school in China had developed a totally new rules to follow by the order under this school. However, they didn't change the Vinaya they used but they set the rules parallel with the Vinaya and use at the same time.