Japan Airlines flight JA1732 (Hong Kong-Fukuoka-Chitose) encountered turbulence over Miho VORTAC, resulting in serious injuries to 2 passengers, minor injuries to 24 passengers, minor injuries to 4 flight attendants, and part of the cabin was damaged. Thereafter, the aircraft continued its flight and landed at Chitose Airfield at around 18:30. The investigation of FDR revealed that the 1st turbulence encounter had “g’s” varying from plus 1.98 to minus 0.16 and then to plus 1.49 of about 0.5 seconds duration. The 2nd turbulence encounter was 5 seconds after the first one with “g’s” varying from minus 0.16, plus 1.51, plus 0.71, plus 1.49 and to plus 0.68 of about 25 seconds duration. Cause: It is recognized that this accident was caused by the aircraft encountering turbulence caused by cumulonimbus clouds while flying at cruising altitude.