Ford
Wade
A tsunami is coming, and you want to walk over it, so you have to ford it. You don’t walk across a tsunami, you wade across it.
しょう
わた
None
Your ability to ford this tsunami impresses everyone who witnesses it, especially the Shougun (しょう). Now that you've taught him a tsunami can be forded, he's going to start sending his troops through them instead of waiting for them to pass.