1924: Earthquake resistant construction regulations were introduced. After the 1891 Mino-Owari magnitude 8 earthquake, research and study into earthquake resistant construction began. The 1923 Kanto earthquake further hastened the introduction of building regulations. The regulations required a minimum thickness for wooden beams, reinforced concrete to have an earthquake load and braces to be installed. However, these rules only applied in town areas - See more at: http://japanpropertycentral.com/real-estate-faq/earthquake-building-codes-in-japan/#sthash.4XjqDL19.dpuf