Bring water to a boil in a medium sized pot. Add a block of konnyaku. Boil for 10 minutes. Drain and discard water.
Cut konnyaku lengthwise into 2 even blocks and make ½” thick cubes out of them. Then, take each cube and make small cuts both horizontally and vertically to allow liquids to penetrate. Set aside.
Place a skillet over high heat. Add cooking oil. Then add cubed beef and brown on both sides. Remove from the pan with a slotted spoon. Use remaining fat to sauté the konnyaku so the surface is slightly blistered and browned. Remove from heat and set aside.
Place beef and konnyaku, dashi, soy sauce, mirin and sake in a medium saucepan. Bring to a boil, then lower heat and simmer 1 to 1 ½ hours until the beef and konnyaku are tender.
Add miso paste and stir until dissolved.