Board Thread:Naruto Discussions/@comment-36512555-20191224052011/@comment-30323490-20191224075139

I think you usually needs scrolls to summons objects (Such as weaponry).

Where as summoning living beings, things aren't exactly clear. For instance, Pa could summon Naruto yet he didn't have a blood contract with him (that we know of at least). Yet usually when you summon a living being, you use a blood contract.

I think it's more of a chakra base thing than a blood thing. Madara and Obito could summon Kurama yet i don't think that Bijuu bleed.

Flying thundergod works like the summoning technique, yet you don't need blood contract for it. You just teleport somebody from mark 1 to mark 2, and the mark is most likely chakra based.

The rinnegan user can summon its path thanks to the rinnegan rods, which can handle chakra.

So probably a blood contract is chakra based as well.