Having travelled in Malaysia, Indonesia and Singapore, I was impressed by the large presence of ethnic Chinese in all three countries. I looked up some numbers on Wiki and it looks like they make up a significant portion of the population in most countries in the region but there doesn't seem to be much information about their history and culture. I'd love it if anyone could provide me with more insight about them because, from my very limited experience, they seemed to be an interesting group.
In Malaysia the first Chinese immigrants arrived during the Ming dynasty in the port of Malacca. However, trade between Malaya and China had ceased by the time Portugal seized the city and the community became isolated from China proper, eventually assimilating to a certain extent (look up 'Peranakan').
Later, the Malay rulers in the 18th and 19th century began hiring Chinese workers to exploit the tin mines in Malaya. The practice continued once the British fully took control. The Chinese labourers organised themselves and became businessmen in their own right. Many are the tales of penny-less immigrants from China who came to Malaya and made it big. For example, the ethnic Chinese tycoon, Yap Ah Loy, is considered responsible for the construction of Malaysia's capital, Kuala Lumpur.
To a certain extent, the Chinese formed the entirety of the non-European capitalist class. They maintained their links to the Chinese mainland through the fall of the Qing and Republican rule. Sun Yat Sen famously spent his exile in Penang. When the Japanese invaded mainland China, the overseas Chinese in Malaya and elsewhere helped fund the resistance, which led to severe reprisals when the Japanese invaded Southeast Asia.
With the Communist takeover, however, most business ties were broken for about half a century. With liberalisation in China, these are being reestablished.
In Malaysia, the Chinese business class faced a backlash from the majority Malays, and the government imposed quotas in public company ownership, university admissions and elsewhere. However, the Chinese remain wealthy and dominate any list of richest Malaysians even today.
In Indonesia (and other malay region), the ethnic chinese is divided into several categories. Cina totok (the one still follow the culture), Cina Benteng (Mixed with the local culture already) and Non chinese chinese (the one who let go of their culture and become like local).
In general, all of them is included into peranakan group
There is a new culture emerging which is new chinese (mainland or the surrounding area) fresh off airplane. Due to the disconnect between Indonesia and China after G30S (allegedly by PKI), the culture of Cina totok and the recent immigrant is somewhat different. Partly because of the law which require Indonesian Chinese ethnic to change their name into Indonesian(or western) sounding name and the ban on doing chineseee culture in public spaces. So most Cina totok is generally Indonesianized.