Why does Vietnam mainly use blue pens?

Living in Vietnam, you will notice that the standard pen color used is blue. When I ask Vietnamese people, "Why blue?" I would like to talk about the national regulations regarding blue ink, the background behind the spread of blue ink, and Vietnamese people's recognition of blue ink. In this article, I would like to write about the national regulations on blue ink, the background of the spread of blue ink, and the Vietnamese perception of blue ink.

Sign official documents in blue ink.

The Protocol 30/2020/NĐ-CP stipulates that signatures on official documents in Vietnam must be signed in blue ink. In the past, the law did not specify the use of blue ink, so black ink was also acceptable, but the law has been amended to require the use of blue ink. The reason for such a revision is that administrative documents are usually prepared in black ink, so it is difficult to tell whether the signature is an autograph or a copy if it is signed in the same black ink. It seems that the decision was made to use blue ink, which is already in common use.

Habit of writing in blue since childhood

In Vietnam, blue ballpoint pens are also used by students to write on the board in their notebooks and to fill in answer sheets for exams, but there is no particular requirement to use blue ink for official exams (e.g., entrance exams). Although black ink can be used, it is common practice to use a pen with blue ink. The Vietnamese have a notion that documents written in blue ink look best, and this is said to be one of the reasons why blue ink is preferred.

There are several theories as to the history of the spread of blue ink over black, including that blue ink was less expensive than black ink at the time, that blue ink is more resistant to fading than black ink, and that black was the color used for writing with a brush and blue was preferred for other types of writing, but the truth is unclear.
In case of mistakes, they are corrected with correction fluid or other means. The reason why pencils and mechanical pencils are not used for exams is to prevent them from being easily erased, and also to prevent cheating. But when I heard this, I thought, "Doesn't it matter whether I use a pencil or a ballpoint pen when I cheat?
Vietnamese offices usually stock more blue ballpoint pens than black ones, and it would be safer to get into the habit of using blue pens rather than black ones for Vietnam-related documents.

author (usu. of a particular book, etc.)