Rīmu-x does not appear in the "standard" version of the Assyrian King List [http://oracc.museum.upenn.edu/riao/kinglists/assyriankinglist/index.html#Section5-7] (AKL), nor are any inscriptions of this monarch known. As such, his exact position is subject to much debate. Rīmu-x's name is partially preserved in a fragment of a different version of the AKL, VAT 9812 [http://oracc.museum.upenn.edu/riao/kinglists/fragmentvat9812/index.html#List]. Here he is listed along with Mut-Aškur [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/mutashkur/index.html] and possibly also Asīnum [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/asinum/index.html] (Landsberger 1954, 42-43). If this is the case, then he may have been a member of the Samsī-Addu Dynasty. Julian Reade suggests that Rīmu-x was the ruler at Ekallātum, and that Asīnum [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/asinum/index.html] may have been his governor at Aššur, or another member of Samsī-Addu [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/samsiaddui/index.html]'s family who was a contemporary of Rīmu-x in Aššur (Reade 2001, 6). Reade also remarks that Irving Finkel has suggested that a-sí-nim may correspond to the noun assinnu (priest of Ištar). If this is the case, Reade states that assinnu may have been a nickname for Rīmu-x and that Asīnum [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/asinum/index.html] and Rīmu-x may consequently be the same person (ibid). Gashe et al. support the theory that Mut-Aškur [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/mutashkur/index.html] and his successors ruled in Ekallātum as part of the Samsī-Addu Dynasty [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/index.html] (Gasche et al. 1998, 52). They suggest, however, that these kings ruled during approximately the same period that Aššur-dugul [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/sonsofnobody/ashurdugul/index.html] and his successors occupied the throne in Ashur.
Poppy Tushingham
Poppy Tushingham, 'Rīmu-x', The Royal Inscriptions of Assyria online (RIAo) Project, The RIAo Project, a sub-project of MOCCI, 2021 [http://oracc.museum.upenn.edu/riao/fromsamsiaddutomittanicilent18081364bc/samsiaddudynasty/rimux/]