In Japan, green teas are categorized as first, second and third based on when it is being harvested.
This is also called "New Crop" (or Shin-cha). Since it is the first harvest, this is refereed as "Syun" or seasonable (Japanese culture value the concept of "Syun". An example of it is the famous Haiku, where the word “Syun” must be used in the short poem). The characteristic of the first harvest is the still “young” tea leaves, which are richer and clearer in aroma.
Compared with the second and the third harvest, first harvest contains less catechin, which brings less astringency. First crop also has less caffeine, but has more amino acid, which is the prime component of the sweetness and umami element.
Green tea plants take in nutrients during winter, and deliver the nutrients to the leaves as it blooms in spring time. Traditionally in Japan, the first day of the spring is February 4th and it is called Rissyun (literally translates to "spring stands up") and the 88th night is considered to be the best first day to pick green tea. It is believed that by consuming the tea leaves harvested on this day, a healthy year lays ahead of the consumer. Therefore, the first crops are popular gift items in Japan.