Kombu Onigiri (Kelp "Tsukudani" Rice Ball)

Ingredients

• 50-60g used kombu kelp (approx 1 sheet - 12g when dry)
• 500ml water
• 2 tbsp sake
• 1 tsp rice vinegar
• 1 tbsp brown sugar
• 1 tbsp mirin
• 2 tbsp soy sauce
• 1/2 tbsp sesame seeds
• 600g cooked rice (300g or 2 rice cups before cooking)
• 1 bowl of ice cold water
• 2 tsp salt
• 5-6 pieces of nori cut to onigiri size (1 sheet of sushi nori will be enough for approx 4 onigiri)