The Heart Sutra is a Buddhist sutra that is essentially all the realisations Gautama Buddha had when he reached enlightenment. In essence, the sutra states 'emptiness is form, form is emptiness'. It was compiled by around 500 arhats, or Buddha's direct disciples, who got together and put all of Buddha's realisations into a digestible format. Well, the whole thing is not exactly digestible.

The Heart Sutra is split into 60 tomes, each about 2 or 3 inches thick, and each different. I'm not sure how many people have memorised the entire Heart Sutra, but the version I have memorised is a much shorter abridged version that is very common in all Mahayana Buddhism temples in Japan.

It takes about 3 minutes to read through the abridged version of the Heart Sutra at an ordinary pace. But it took me more than a year to remember because I was trying to remember it through Yamabushi training, which wasn't very effective. Put simply, I wasn't training enough to remember it. Instead, I sat down and tried to memorise it, which really helped in the end. To do so, I read through it hundreds of times, closing my eyes along the way, and constantly testing my memory.

In the end, it was very much worth it. Not only can I say it fluently during our prayers in Yamabushi training, which is amazing when you're alongside others who can do it too, but it is also there when I feel stress. I just start saying it, either out loud or in my mind, and focusing on the sounds coming out helps. Since I've memorised it, the sounds just flow too. Sometimes when I'm meditating, if my mind becomes restless, I find saying the Heart Sutra helps me relax too.

Here is a cool video of the Heart Sutra. I think listening to this constantly would be an excellent way to remember it. The Heart Sutra would have originally been learned by monks listening to it too, as many of them couldn't read.

Now my challenge is much harder. Well, much longer would be more appropriate. There is one more long prayer I have to memorise called the Sanzan Shukuji (at the bottom of the third page here in Japanese). This one is just going to be more of a long slog. I guess I better get to it!

UPDATED November 2022: I finally memorised the Sanzan Shukuji!