Japan has squat toilets in some places. They're just troughs in the floor, basically, and they're kinda freaky and weird, and it is perfectly reasonable to decide that they are outside your comfort zone and that you will avoid them in favor of Western-style toilets.
You should still seek one out and give it a go when there's no particular urgency and you can take the time to figure out the logistics of using one.
Because that way, when the situation is urgent, and that turns out to be the only available option?
Yeah. You'll be glad you did. (I certainly wished I had.)