TeaHQ

Koshun

One of Japan’s explicitly aromatic cultivars, bred for a floral, almost citrus-peel top note that is unusual in a category built around umami and marine depth. It gives producers a way to make a Japanese green tea that smells like an oolong without changing the processing, and it has become a favourite of small growers looking for something that cannot be confused with a Yabukita blend.

香駿Camellia sinensis var. sinensisJapan

Where it sits in the botany

Koshun is recorded under Camellia sinensis var. sinensis, the variety group one level above cultivar. It is associated with Japan, which is where it was selected or is most widely planted rather than the only place it grows.

Also transliterated as: koshun, kōshun.

Where it came from

A Shizuoka aroma-focused selection released in the early twenty-first century, one of a small group of cultivars bred for fragrance rather than yield.

How firm this is: Inferred rather than taken from a primary breeding or registration record. The aroma-breeding intent is consistently reported; the release year and parentage were not verified against a primary source.

What the plant is like

Strongly aromatic, moderate yield, and responsive to lighter steaming — deep steaming tends to bury the very character it was bred for.

Why a grower plants it

Yield, hardiness, when it buds, what it resists and whether a machine can cut it. This is the half of a cultivar’s identity that decides what is actually in the ground, and it is usually left out of writing aimed at drinkers.

Moderate yield and responsive to lighter steaming, which constrains who can use it: a factory set up for deep steaming will bury the character the plant was bred for, so growing it implies a processing commitment as well as a planting one.

What it does in the cup

Reported as floral with an almost citrus-peel top note — a cultivar that lets a producer make a Japanese green tea that smells like an oolong without changing the processing.

How much of this is really the cultivar?

The aroma here is genuinely the plant, which makes it one of the stronger Japanese cultivar claims — and it comes with a condition attached rather than an assurance. The same cultivar deep-steamed is an ordinary sencha. A cultivar name on a Japanese tea therefore tells a reader what was available rather than what arrived, and the steaming grade tells them how much of it survived.

Cultivar, growing site and processing all shape a cup, and the cultivar is very often the smallest of the three. It is also the one that fits on a label, so almost every commercial incentive runs toward overstating it. This section is on every cultivar page that has been reviewed for it, including the ones where the honest answer is “less than you would think”.

What it is usually made into

The categories this cultivar is typically processed into. It is a statement about common practice, not a limit — processing decides the category, and a cultivar can be taken down more than one route.

  • Green tea — Tea whose oxidation is halted early by heat, keeping the leaf green and the cup fresh, vegetal or marine in character.

Teas in the catalogue made from Koshun

Other cultivars in Camellia sinensis var. sinensis

Guides covering this cultivar

  • Cultivars bred for smell — Most tea cultivars were selected for yield, hardiness and budding date. A small and growing group was selected for aroma, and the teas made from them are the clearest evidence available that a plant contributes something processing cannot supply.

Sources

  • TeaHQ editorial synthesis — TeaHQ

This page is TeaHQ’s own synthesis throughout. No breeding register or institutional record stands behind the account above, which is why the origin note carries its confidence in the open rather than reading as a citation.

How TeaHQ handles sources

Written comparisons

Where TeaHQ has set this cultivar against something it is routinely confused with, and argued the differences out in full.

  • Koshun vs Sofu — Japan’s two aroma-bred cultivars, and the pair that shows the country’s cultivar programme reaching for something other than a better sencha. Both are strongly aromatic, both are modest in yield, and both are punished by the processing Japanese green tea usually receives.