This kanji character is rarely used on its own, but is often found combined with other characters.
One meaning is “barrier”. There used to be many post stations along the road from Tokyo to Kyoto. At the mid-way point there was a large gate. This led to people thinking of towns in Japan as being either “West of the barrier”関西 (Kansai), or “East of the barrier” 関東 (Kanto). To this day, the distinction still exists, and there is a fair amount of good-natured East-side/West-side rivalry.
Although this character refers to a barrier, it is found in words related to “connection” such as 関係 “relationship” and 関心 “concern/interest”.
It seems as if, as far as the Japanese language is concerned, a boundary is not only something that can form a barrier between two things, but also something which can connect two previously unrelated things.
Calligraphy by Vicky 