Started a batch of natto this evening. 600g of dry soybeans soaked about 8 hours, then pressure cooked for 20 minutes. Mixed in some spores, put a thin layer of the beans in these glass containers, then covered with a damp cloth and lids. I'll keep these in my makeshift incubator (a cooler with a reptile cage heating mat) overnight at 40C, then put them in the fridge in the morning, and enjoy them the day after.
That looks really interesting! I make lots of tempeh at home, but I've never heard about "natto" before. From reading the wiki I can see that the microorganism is a specific variant of Bacillus subtilis bacteria. Where did you get your spores from?
Get it on aliexpress or taobao.