Seung Sahn was a Korean Zen Master that died in the 1994. When he was 18-19, a monk saw potential in him and taught him a practice technique. The Zen master told him with this technique, he’d either die, go crazy, or get enlightened. He then went into a 100 day meditation retreat in a mountain side hermitage and he lived off pine needles. Accounts say he got enlightened.
I’m not sure if that’s true or not, my suspicion is he probably realized emptiness. When he came out, his teacher told him to familiarize himself with the idea of “don’t know,” which he popularized in the West. Even though he pushed it forward, I think this phrase really was started by Bodhidharma, who is credited for transmitting Zen to China. The emperor of China asked him who he was, where he replied “I don’t know.”
“Don’t know,” I think is a very profound answer, especially when understood in the right context. Otherwise, I feel it becomes a Zen one-liner like “being one with everything.” I actually don’t have any understanding or realization of all of this, but I would hope to one day =D
There aren’t many videos of him unfortunately, and there are only a few online. It’s short and does its job.