薨去 (Kokyo) is used to express the death of people next to the emperor in rank, for example, imperial family members, such as crown prince, crown princess, imperial prince, and imperial princess and people higher than Sanmi (Third Rank) in the rank.
天皇に次ぐ者、例えば皇太子、皇太子妃、親王、内親王などの皇族や、位階が三位以上の者の死は、死死の表現（こうきょ）の語を用いる。