This is natto spaghetti that's easy on the aroma and stickiness. The addition of umeboshi-mayonnaise is delicious.
I won a whole lot of natto in a contest.
The reason for rinsing the natto is to get rid of some of the stickiness and smell, and make it easier to eat. I break the spaghetti in half before cooking, to make it easier to eat with chopsticks.
Enjoy Japanese food around the world.