How to Write a Message or Email to Your Boss in Japanese

A quick guide to writing a message or email to your boss in Japanese
Everyone needs to send a mail or message to a Japanese colleague at some point, for example to ask for (paid) leave.

A proper Japanese email has these parts: 宛名 (atena: recipient)、挨拶 (aisatsu: greeting)、名乗り (nanori: giving your name)、要旨 (youshi: the main point)、詳細 (shousai: details)、結びの挨拶 (musubi no aisatsu: closing greeting)、署名 (shomei: name, signature).

You can use the following as a model:

○○ 部長(ぶちょう) To: Department manager….
お疲(つか)れ様(さま)です、ナムです。Hello (translated this way for Vietnamese; inside a Japanese company people always greet like this). My name is Nam

繁忙期(はんぼうき)に大変(たいへん)申(もう)し訳(わけ)ないのですが、私用(しよう)により、….月(がつ)の◯日(にち)(。。。曜日(ようび))に有給(ゆうきゅう)休暇(きゅうか)を取(と)らせていただきたいと考(かんが)えております。
I am very sorry to ask at a time when the company is so busy (the busiest season), but for personal reasons I would like to take paid leave on … (which falls on …day)

ご迷惑(めいわく)をおかけしますがご了承(りょうしょう)の程(ほど)、よろしくお願(ねが)いします。
I know this causes inconvenience (affects the work), but I would be grateful for your understanding and approval.

※Vocabulary:
1）繁忙期（はんぼうき）: Busy season (for example when a company has many orders, the end of the year…)

2）私用（しよう）: Personal matters
Usage: 私用により/私用があるため: because of personal matters

3）有給休暇（ゆうきゅうきゅうか）を取る（とる）Take annual (paid) leave

4）ご迷惑（めいわく）をおかけします: To cause inconvenience (humble form used by a subordinate; polite). Among friends you can simply say: 迷惑（めいわく）をかける

5）ご了承（りょうしょう）の程（ほど）、よろしくお願（ねが）いします。
I would be very grateful for your understanding and approval.

Source: Akira Akira

See also:
Guide to Writing Emails in Japanese
The Polite Form of できない in Japanese