Five of them on the army map
This is from Colonel(retired) John Taylor, who served on the India-China border in Ladakh in 1970.
As a young officer with just about six years of service, I was provided with a detailed map on which the boundary had been marked along with Chinese troop deployments (there were just a few). The map did not have just one boundary. It had many:
a. The McMohan Line (prepared by and named after the first British Surveyor General of India).
b. The Tibetan Boundary (as per documents left by the British army).
c. The 1962 Indo-Chinese Dispute Line.
d. The Indian Claim Line.
e. The Chinese Claim Line [Rediff]
When you next read a media report about the Chinese transgressing across the boundary, do ask which of these five boundaries was actually violated. That should help understand matters better.