Japanese bourse tumbled in the morning session. As tensions in the Middle East shored up energy prices, market was concerned that Japan's economy may cool down, prompting investors to seek safe havens. The Nikkei opened 808 points lower, and initially narrowed the slump to 577 points, peaking at 55,701 before ebbing back. It collapsed 2,215 points to a low of 54,063, ending the half-day down 2,188 points or 3.9%, at 54,090.In the AI and semiconductor sectors, SoftBank (9984.JP), which had its rating outlook lowered by S&P, nosedived 7.3%. Advantest (6857.JP) and Kioxia (285A.JP) slid 5% and 5.5%, while Disco (6146.JP), Lasertec (6920.JP), and Tokyo Electron (8035.JP) plunged 4.1-4.6%. In heavy industry stocks, Mitsubishi Heavy Industries (7011.JP) stumbled 6.6%. Kawasaki Heavy Industries (7012.JP) and IHI (7013.JP) cratered 9.1% and 9%.