貫 pierce

ONYOMI: KAN

Let's call that extra horizontal line a piercing which goes through the mouth!
Now we can say. ..
It takes money for Genghis KHAN to get his mouth pierced.

KUNYOMI:

つらぬ＊く

to penetrate all the way through: not just violently. (for example, 'The river runs through the town.') Also to see a project all the way through to the end (KANA)