The real story is that we fortified our small lot. There has not been a castle in Kashima City for hundreds of years, but I feel like there is now. We bought heavy golf netting, cut it into three strips about 3/4 of a meter wide and eight meters long and used metal posts woven through the net and pounded into the ground to stretch the net along the lenth of our hedge.
We then attached the top of the netting to the hedge using gardening ties and pounded tent stakes into the ground at the base to make it taught so they can't slip under it. The hedge is thick, so blocks them above a level of anywhere from 10 to 40 cm from the ground. The other three sides of the lot have concrete walls and the driveway is blocked by an acordion gate. To top it off we bought some sand that has a stong medicine smell to it and is supposed to repel dogs. We put some at the gate and some at the point where the strays used to enter. It only has a range of about 1 meter, so it doesn't bother Momo. Actually, I don't know if that stuff works or not, I just wanted to do something non-life threatening to those dogs for spite.
It is a bit of an inconvenience to have to open and close the gate each time we leave, but at last Princess Momo in her Naka Castle can enjoy her toys in peace, and we can all sleep at night.
No longer able to get into our yard, they have stopped hanging around. Perhaps in a few weeks time, or less, they will move on to find easier pickings....in Aso Town perhaps!