Place the flour, water, kansui and salt into a stand mixer bowl
Using a dough hook, bring together to form a dough
Shape into a ball on a lightly dusted surface then cover with a damp cloth and leave to rest for 15 minutes
Use a rolling pin to press the dough until flat enough to fit through a pasta roller on the widest setting
Roll the dough through the pasta roller at the widest setting until it comes together to form a smooth, solid sheet, folding in thirds and turning between each pass
Then pass through the next two settings, one pass per setting
Fold in half lengthwise and pass through the widest setting once
Fold in half lengthwise, cover with a dry towel and leave to rest for 30 minutes
Unfold the dough on a lightly dusted surface then pass through the roller once on the widest setting
Reduce the settings one step at a time, for 3 more passes
Use an angel hair pasta cutter and cut the dough
Dust the noodles with corn flour to separate the strands then cover and set aside to rest for 24 hours *
to cook:
Bring a large pot of water to the boil, add salt then add the noodles
Cook for 90 seconds, drain and rinse under cold water
Add to your broth to make ramen
Notes
* they can be stored after this stage in the fridge for up to 5 days