Write what is actually inside your Letter Pack, rather than only “gift” or “personal items.” The contents field, 品名 (hinmei), helps Japan Post decide how an item can be transported. Japan Post warns that an omitted contents description, or contents subject to air restrictions, can result in non-air transport and delayed delivery. Japan Post: Letter Pack delivery-delay conditions
Name the object, not the reason for sending it
A present is a reason for mailing something; it does not identify the object. Japan Post asks for correct, specific item names and says that some products need additional details to establish whether air restrictions apply. Japan Post: specific descriptions and additional details
The following are hypothetical writing examples, not an approved list of contents:
| Vague entry | More informative entry, if accurate |
|---|---|
| Gift | Cotton T-shirt / 綿のTシャツ |
| Personal items | Paper notebook / 紙のノート |
| Documents and other things | Application documents and paper photographs / 申込書・紙の写真 |
The Japanese wording is provided as an editorial language aid. It is not a guarantee that a specific package is acceptable. Describe every kind of item you actually include, and keep the entry consistent with the contents.
There is no need to disclose the private subject of an ordinary letter just to distinguish it from merchandise. An object-level description such as “application documents” can explain the type without reproducing the letter’s text.
Do not solve uncertainty by guessing an ingredient
Some goods require more than an object name. Japan Post’s guidance distinguishes details such as battery presence or product composition when assessing air transport. A familiar brand or a small package is not enough to establish those details. Japan Post: additional information in the contents field
If you cannot verify a relevant specification, take the item’s packaging or manufacturer information to the counter and explain the uncertainty. Do not write “no battery” or another qualifying statement simply because it would make the label easier to complete. An accurate description reports the contents; it does not change their characteristics.
This guide does not provide instructions for mailing batteries, aerosols or other restricted products. Those need the rules for the specific product and postal service.
Separate three different problems
The contents are prohibited. Letter Pack excludes cash, valuables and dangerous goods, among other restricted contents. Waiting longer does not make a prohibited item acceptable. Japan Post also asks senders to avoid fragile or difficult-to-replace contents. Letter Pack: prohibited and discouraged contents
The item can be accepted but cannot use air transport. For relevant domestic routes, Japan Post says non-air carriage can add approximately one to four days. This is a possible delay, not a promised maximum arrival time for every Letter Pack. Japan Post: non-air delivery
The description does not establish what is inside. The next step is to clarify the information before posting, rather than assuming ordinary speed because the envelope has already been purchased.
These categories should be checked in that order: acceptance first, transport conditions second, scheduling last.
A useful final check before sealing
Imagine that you prepared documents and later added a small gift. This hypothetical change should trigger a new contents check: the original “documents” entry no longer describes the complete mailing. Review the added object, its packing needs and any restrictions, then update the description.
Read the final label against the items laid out in front of you. If a deadline matters, ask about the actual origin, destination and contents; neither a detailed label nor a prepaid envelope proves that an item will travel by air.
This is desk research of domestic Japan Post rules, not a test mailing or an acceptance decision for a particular product. International customs labels have different requirements. Letter Pack’s tracking also does not provide compensation for loss or damage, so consider the consequences of a problem before sending anything hard to replace. Japan Post: Letter Pack compensation conditions