According to Japanese customs regulations, there are usually restrictions on the quantity of tea that individuals can bring into the country. Generally speaking, it is usually allowed to bring small amounts of tea for personal use. However, 4 kilograms of tea may exceed the limit for personal items.
It is recommended that before you bring a large amount of tea to Japan, you first check the specific regulations of Japanese customs to understand the quantity limit and declaration procedures for personally carrying tea. Generally, bringing large quantities of tea requires advance declaration and may require payment of customs duties.
If you are unsure, you can contact Japanese customs or the airport customs department before departure to inquire about the specific carrying amount and declaration procedures. This ensures that your tea will pass customs smoothly.