In what episode does Goku go Super Saiyan Blue for the first time?

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Goku goes Super Saiyan Blue for the first time in The Anime Dragon Ball Super Episode 24 with the title: “Clash: Frieza vs Son Goku! This is the Fruit of My Training!” 

 

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Episode Summary:

Goku and Frieza/Freeza continued their battle, testing each other out. During a short pause of the battle Frieza starts to express his resentment toward Goku and about taking revenge, he then starts to fire energy blasts at onlookers starting with Krillin.

Goku vs freeza Freeza attacks Krillin

Sometime after the battle resumes Vegeta interrupts it by kicking Goku. He did this because he was angry that they were not fighting at full power. A small fight then ensued between Goku and Vegeta which was stopped by Frieza. After a small exchange of words beween Goku and Frieza, Goku Transforms in to Super Saiyan Blue.