What are the fundamental skills of Judo?

What are the fundamental skills of Judo ?

Ready Position : The combatant tries to grab his opponent quickly and throws him of balance.
Gripping: The judoka who successfully grabs his opponent (kumi kata) has the advatage. Positioning : The seized combatant tries to escape from the kumi kata, while his attacker prepares the next throw.
Throwing : After throwing his opponent off the balance, thereby depriving him of his powers of self-defence.
Pinning : The attacker increases the pressure on his opponent’s body as quickly as possible, especially on the shoulders.
Choking : Using his hands and opponent’s jacket, the attacker cuts off breathing by compressing his trachea, in order to reduce the flow of blood.
Arm Lock : The attacker holds to his opponent’s arm while pulling it as straight as possible.