法令翻訳 http://www.japaneselawtranslat...amp;page=4

(吸収分割の登記)
第九百二十三条   会社が吸収分割をしたときは、その効力が生じた日から二週間以内に、その本店の所在地において、吸収分割をする会社及び当該会社がその事業に関して有する権利義務の全部又は一部を当該会社から承継する会社についての変更の登記をしなければならない。

Registration of an Absorption-Type Company Split
Article 923   When a Company effects an Absorption-type Company Split, the registration of a change must be completed with regard to the Company effecting the Absorption-type Company Split and the Company succeeding to all or part of the rights and obligations held by such Company in connection with its business by transfer from such Company, at the location of the head office, within two weeks from the day on which the Absorption-type Company Split became effective.