In a pot, soak the konbu seaweed in 1000 ml of water for about 20 minutes. Turn on the heat and bring to a simmer.
When the water starts to simmer, add the curry base and mentsuyu. Simmer over medium heat and dissolve the curry roux.
Add the other ingredients starting with the ones that take longer to cook, such as the meat and stalk of the napa cabbage.
If you add the ingredients gradually as you eat, they won't be over-cooked.