Those 10 day retreats book out months in advance. They are in the style of Goenke, a Burmese master who came up with a sort of Vippassana’s greatest hits. For a drop in, Chiang Mai is the place I did 90 days of silence at the Insight meditation Society in Massachusetts. It changed my life. I did it again at Kopan Monastery in Kathmandu. But 10 minutes twice a day of mindful breathing will take most people as far as they want to go. I admire the OP. I lived for a while in a gaijin house in Kyoto. The green peace guest house, much beloved in the lonely planet era. I had about 10 inches of walk around space with a meter wide futon in the middle and a shelf over the bed and a few hooks for my stuff. Great, great days.