"Entering"???
Where has the writer been for the last 100+ years?
A lot of the incidents listed below, and in the link, definitely are not "peace", and most can be construed as "acts of war" by almost anyone looking at them objectively. Some/most have chosen not to do that since they are over-matched by the Chinese military in the region.
Things apparently kicked off at least as far back as the early 1900s.
Began to get more serious in 1956.
In 1988, China killed 64 Vietnamese, most of whom were unarmed "14 March 1988 China defeats the Vietnamese navy in the Johnson South Reef Skirmish on Mabini reef (Johnson South Reef), killing 64 young Vietnamese, most of them unarmed,[50][51][52] after the Vietnamese tried to intercept a Chinese force commissioned by UNESCO to build a tidal gauge station[48] in the Philippines claimed 200 Nautical mile Exclusive Economic Zone".
In 2001, a Chinese military jet collided with a US surveillance aircraft 70 miles away from Hainan Island, over the South China Sea. The Chinese pilot lost his life due to his error. The American EP-3 plane, and its 24 crew were held in China for quite some time, before eventually being released:
link
On the 8 January, 2005 "Chinese ships fired upon two Vietnamese fishing boats from Thanh Hķa Province, killing 9 people and detaining one ship with 8 people on Hainan Island.[63]".
In 2009, "The Pentagon reported that Chinese ships harassed a US surveillance ship. According to the report, five Chinese vessels "shadowed and aggressively maneuvered in dangerously close proximity to USNS Impeccable, in an apparent coordinated effort to harass the U.S. ocean surveillance ship while it was conducting routine operations in international waters." The crew members aboard the vessels, two of which were within 50 feet, waved Chinese flags and told the US ship to leave the area, the statement said.[65]"
25 February 2011 "The Chinese frigate Dongguan fired three shots at Philippine fishing boats in the vicinity of Jackson atoll. The shots were fired after the frigate instructed the fishing boats to leave, and one of those boats experienced trouble removing its anchor.[67][68]".
Since at least Jan. of 2015, "China has been transforming Mischief Reef into an island since January.[138] According to UNCLOS, artificial islands do not afford the occupying nation territorial waters.[139]".
There have been many, many other incidents of purposeful collisions by naval vessels, as well as gunfire by the Chinese on vessels and crews of other nations in the region, not listed above see the link below for more info:
link