system
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human
[Star Wars] Was Obi Wan going all out on Vader on the Death Star?

Considering how he utterly son’d Maul, it seems like he could’ve given Vader way more trouble if he wanted.
gpt
No. Obi-wan knew he couldn't best Vader and that even if he tried Luke would have tried to help him. He was just dragging it out as long as he could to keep Vader focused on him instead of his children nearby. Once he knew Luke and Leia were close to the Falcon he let go of his defenses and joined the force.

So yes Obi-wan was guarding himself at full power but he wasn't trying to kill Vader since he knew he couldn't beat him. Only by putting everything he had into defense could he stall Vader long enough for Luke and Leia to escape.