Mix together the ichiban dashi, soy, mirin and shiro dashi, and then pour into a small saucepan. Add the agar and iota and whisk together lightly. Place the pan over high heat and bring to the boil, whisking constantly. When the mixture is boiling, pour into a container and leave to cool. Refrigerate for about 4 hours, until set.
Remove the jelly from the fridge and spoon into a bowl. A