When “締” fills a head
Why it is in the set
Because a deadline occupies a head differently from the work itself. 課 is the task; 締 is the date, sitting there taking up room whether or not you are doing anything about it. The two are separate characters for that reason and the reading tells them apart.
What a head full of it looks like
Counting backwards from Friday. Waking up briefly at three with the date in mind. Being unable to enjoy Sunday properly. A head led by 締 is not working; it is being watched by a calendar.
Words that use it
締め切り (shimekiri, a deadline), 締める (shimeru, to tighten or fasten), 取締役 (torishimariyaku, a company director), 月末締め (getsumatsujime, the month-end close).
Kanji it turns up with
焦 (panic) behind 締 is the week it is due. 遊 (playing) behind it is the joke that writes itself.
Where “締” comes from
The thread radical 糸 on the left, 帝 on the right for the sound. Thread being pulled tight.
締め切り (shimekiri) is the ordinary word for a deadline, and it is literally “tighten and cut”: the moment the thread is pulled closed and the end snipped off.
The same character does up a belt (ベルトを締める) and closes the books at month end (月末締め).
A line you might get for “締”
“The date is known. The work has not been told.”
Count the “締” in your own headOthers in “Everyday”
“締” is filed under “Everyday”. These are the rest of that group.
The 36 kanji
This is entirely a joke and has nothing to do with any real person.