I guess I'll begin with the explaination on Summoning Jutsu and then move onto Toad Summoning.
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Jiraiya walks over to his sensei and sat down beside him.
"Uummm... I'm a newbie, so my knowledge is kind of basic. I looked around some scrolls and this is what I learned."
Jiraiya then starts reciting:
Summoning Technique:
It is space-time ninjutsu used to summon or call upon an object or an animal with which the user has already signed a contract. It is a very useful technique because one can instantly transport animals and other objects that are far away and physically would take a long to reach the user's current place. Once a shinobi has signed a contract with an animal, he can summon them by taking a small amount of his blood and wiping it on the contract scroll or on the other hand and then by molding enough chakra then placing their hand on the ground where he wishes to summon his animal.
Summoning Contract:
It is a contract signed between the summoner and the animal whom the summoner wishes to summon during a battle or on other occasions. To sign a contract with an animal one must take some of his/her own blood and sign his name on the scroll provided by a higher rank shinobi who has already made a contract with the said animal.
Summoning Toads:
Toads summons are one of the most powerful summons in narutoverse and are very special since they are the dwellers of the Mount Myoboku which is located in the land of toads. Toad summons specializes in Water and Oil techniques but some of them are also experts in other fields like Tai-Jutsu, Kenjutsu, Senjutsu and other ninjutsus. They vary greatly in sizes, ranging from huge summons who are capable of even dwarfing tall trees and rocks, to small toads who are about the size of regular toads. Some toads are also used for a very specific job like keeping the scroll, transporting humans and objects by carrying them in their bellies and taking them to the desired location (shown during Jiraiya's infiltration of Amegakure) and also to trap the enemy in their belly.
Some of the most prominent Toads of Mount Myoboku are:
1. Gamabunta.
2. Gamahiro.
3. Gamaken.
4. Gamatatsu.
5. Gamariki.
6. Gamakichi
7. Fukasaku
8. Shima.