Japan's hanami and Vietnam's Tết blossoms are both customs of admiring spring flowers. They differ in one structural way: whether people go to the blossom, or the blossom comes to the people.
It started with plum
In the Nara period, "flower" in Japanese meant plum. Aristocrats admired plum trees that had arrived alongside Chinese learning — that was the first hanami.
The shift to cherry came in the Heian period. The Nihon Kōki records a cherry-blossom banquet held by Emperor Saga at Shinsen-en in 812, often cited as one of the earliest records of hanami. In time, "flower" in waka poetry meant cherry without further specification.
Why the whole country blooms at once
The reason Japan can speak of "full bloom" as a national event comes down to one cultivar: Somei-yoshino.
It spread from the late Edo into the Meiji period and is propagated by grafting. Every Somei-yoshino in Japan is therefore a near-identical clone. Under similar conditions they bloom together — which is what makes the sakura zensen, the blossom front moving from south to north, a meaningful idea.
From opening to falling takes roughly a week. That brevity is what makes the occasion.
Holding the spot is a job
At a company hanami, holding the spot is real work: arriving in the morning, spreading a sheet, and sitting there until everyone else turns up. By custom it often falls to the newest employee — and it is among the most baffling instructions a foreign employee receives.
Assigned without explanation, sitting on a sheet for hours looks arbitrary. One sentence of reasoning changes how it lands.
Vietnamese blossoms live indoors
Vietnamese households display blossom at Tết: hoa đào, peach, in the north; hoa mai, yellow apricot, in the south. Different climates, different flowers.
What differs more is placement. The whole tree, or cut branches, is brought into the house. Choosing a tree at the market and carrying it home on a motorbike is one of the standard sights of the weeks before Tết.
The blossom stands at the centre of the home that receives guests. There is no custom of going out to eat and drink beneath the trees.
Inviting each other
Inviting a Vietnamese colleague to hanami works better if you mention the part about sitting on the ground outdoors. Someone expecting only to look at flowers will arrive dressed for something else.
And a Japanese guest visiting a Vietnamese home at Tết should say something about the peach or apricot tree in the front room. The household chose that tree and carried it home.