In Japan there's apparently a saying "Sakura wo kiru baka, ume wo kiranu baka", which roughly translates as "Twerp as prunes a cherry, idiot as doesn't prune a plum".
Not wishing to be condemned as an idiot, I got to work with my pruning scissors.
But first I consulted the interweb, because it really isn't obvious where to make the cuts. However, I found a very helpful website with the following pictures on it.
With these as my guide, I got cutting. It's a fairly savage business, because nearly all of last year's growth is amputated.
The result is a very stumpy-looking tree, much reduced from the many-tentacled thing that we saw in spring. I had assumed that the wilted-looking leaves that were folded in half along the long axis were a sign of stress due to the prolonged drought. But according to a garden shop lady (more about her later) who visited the other day, it's a sign of good health. Could have fooled me...