Naughty Elephants Squirt Water

I have been trying to learn a little about the origins of Kyoto & in particular, reasons for its grid layout. Our house apparently stands just inside what would have once been the outer edges of the original imperial palace grounds, so the Heian-kyo city plan is something I have been trying to find out more about. I have seen a few old map-shops in town but have yet to go inside, maybe when things open up again..

I was always totally useless at history in school & I certainly haven't got far with this. If anyone has reading recommendations, please feel free to share.. : )