These are very fluffy, white kelp slivers. The difference between the two is the type of knife used to split the kombu into thin slivers. This skill is practiced by elite shokunin, specialists in this art.
Oboro and Tororo are not cooked or heated in any way; it is made using rice vinegar to "cure" the kombu, and it becomes very soft. This means all of the essential minerals and vitamins are kept; there is no denaturing of amino acids due to the application of heat.
Oboro and Tororo can be sprinkled on rice as a condiment, or are often added to soba or udon dishes as a flavoring. In sushi restaurants it is placed on top of the sushi.
