Why is Vietnam COVID-19 cases so low compared to other major SE Asian countries?

Like Vietnam's coronavirus cases are like...only 204 cases? There seem to be barely any increase at all in the cases of Vietnam; the number of new cases are so small lmfao its fucking ridiculous!!

That's very rookie numbers and so little compared to other ASEAN countries like Malaysia, Thailand, Indonesia, Philippines where the numbers of cases are literally skyrocketing exponentially every day...! Even Singapore seem to have a bit more increase of Covid19 than Vietnam??...

Like compared these numbers: holy shwit...

Vietnam: 204 cases, 0 deaths
Malaysia: 2766 cases, 43 deaths
Thailand: 1651 cases, 10 deaths
Indonesia: 1528 cases, 136 deaths
Philippines: 2084 cases, 88 deaths (up to increase in 500 cases from yesterday)
Singapore: 879 cases, 3 deaths

I don't want to add Brunei, Cambodia, Myanmar, Laos, East Timor, because they are not main powerful countries in the region and their numbers are very small:

Brunei has like 127 cases and 1 death. Cambodia has 109 cases, 0 deaths (not sure if the government is hiding the actual number of cases or their healthcare system just sucks at detecting cases) while Myanmar and Laos only reported their first cases like only two days ago. East Timor has like only 1 case but their country is so remote and isolated; barely anyone travels there so it makes sense.

So I want to ask how did Vietnam managed to have very low cases compared to other big powerful countries in ASEAN? Whats the secret? Did the government underestimate the number of cases or is there not enough testing of kits or something?

Please tell me your secret. My country Thailand has 1651 cases and 10 deaths, the third highest in ASEAN. A day ago before the exponential rise of Philippine cases, Thailand has even the second most cases after Malaysia.