As Mike-san wrote, you might miss the address. If it's 513 Ranbashi-zaimokuza, the present address is 14-9 Zaimokuza 5chome, Kamakura-shi. Another possibility is 5-1-3 Zaimokuza (= 1-3 Zaimokuza 5chome), but this address started to be used since October 1, 1964, so I think Ranbashi-zaimokuza is more possible. Anyway, I checked the both addresses, and found that Horii family doesn't live there now (Shimazu is at the former address, and Hotta is at the latter).