Pure
A tsunami that's blue is pure. Some tsunami are other colors, like brown or red because they aren't pure, they'll full of trash and poop and other horrible things. But a blue tsunami is completely pure!
Picture this pure blue tsunami. You can see every crystal clear drop of water in it.
せい, しょう, しん
きよ
し
Seeing this pure blue tsunami inspires you to pull out your glowing blue saber (せい)! As the pure water comes toward you, you take one, long slash!
SPLAASHH! The tsunami's pure water splits and it absorbed into your saber. Now it's pure too. And transparent!