When it comes to Chinese cuisine, thereâ€™s a whole lot of variety within itself, mostly based on the culture and what types of spices are available in the various regions in China. Even in chilli sauce alone can vary rather distictly from one province to another.
I cannot say much about Vietnamese cuisine as I havenâ€™t had much experience with it.
Thaiâ€¦hmmâ€¦curryâ€™s a big thing, and it comes in a lot of variety too, with different degrees of spiciness and the main ingredients (fish, beef or chicken) Personally I donâ€™t think Thai and Chinese are similar, for one thing: Thai cuisine uses quite a bit of coconut milk, whereas itâ€™s not the case in any Chinese cuisine. The common denominator: rice as staple food in almost three meals a day.
Korean and Japaneseâ€¦might be similar in ingredients but rather different in spices. Traditional Japanese cuisine are light in flavour/taste, whereas Korean cuisine tends to lean on the spicy side of the spectrum. Also, in terms of presentation, Japanese cuisine also puts in a lot of effort in its presentation of a set meal, makes uses of small bowls and rectangular trays to separate each small dish on the main tray for the set meal. They also stand out as â€œsmall in amount, but highly aestheticâ€ in presentation. Iâ€™d say this is the most significance that sets Japanese cuisine aside from all the above mentioned cuisines in Asia. Most of the others, Chinese, Vietnamese, Thai, Korean etc all prefer to mix things together when they cook.
The reason why one might find similarities between Chinese cuisine and the others is the history behind each region. The Chinese was a great empire in the 19th and 20th century, and exported lots of spices to places around it. The commerce too, meant people were travelling around a lot, and had the chance to try different cuisines when in a new place. When they found it exotic and likable, theyâ€™d try to â€œbring it back homeâ€, be it spices or methods of cooking. Thatâ€™s how the Chinese cuisine has an influence on all Asian cuisines, to a variation of extent.