Far too much salt/sugar/flour. Did you measure your ingredients which has a kitchen scale? The dough was too dry. Did you protect the dough with plastic wrap? Above kneading will crack the gluten and is not going to result in the bread crust really hard. The crust tricky may be https://byd63962.thelateblog.com/29342330/the-definitive-guide-to-shokupan-recipe