霧社事件後，臺灣總督府推動大規模的集團移住計畫，迫使高山原住民遷移至山腳地帶。首當其衝的，是被日本人認為最難管理的布農族與泛泰雅族群（含賽德克族、太魯閣族）。主事者坦承該政策使原住民「舊來勢力關係中斷」。為了釐清集團移住如何分割部落內關係與分離部落間關係，本文重現1931 年布農族與泛泰雅族群部落的社會網絡結構。考察結果顯示，絕大多數親密關係存在於同一個流域之內。受地形阻隔而交通不便的兩部落，即使系出同源，也很少維持親密關係。因此，將部落分割並移至地形阻隔的兩地，可能導致部落內關係分化；將親密往來的部落分離到地形阻隔的兩地，可能導致部落間關係分化。本文具體指出1931-1945 年部落分割的三組案例，以及親密部落分離的七組案例，做為後續研究的指引。

After the Busha Incident of 1930, the Office of the Governor-General launched large-scale collective relocations, forcing mountain indigenous people to migrate to foothill regions. Bunun and pan-Atayal (including Seediq and Truku), who were considered by the Japanese the most difficult to govern, were among those affected. Such policy broke up social relationships among the tribes. This study reconstructed and examined the social networks of Bunun and pan-Atayal tribes in 1931 to shed light on the impact of the collective relocation policy. It was found that tribes inhabiting the same river basin shared strong connections while those of the same ancestry but geographically separated could not maintain close ties. Hence, relocating the same tribe to different regions would disintegrate intra-tribal relationship, and separating different tribes with close connections to locations distant apart would also sever inter-tribal ties. This paper presented three cases of intra-tribal split and seven cases of inter-tribal break-up that occurred between 1931 and 1945 for further in-depth research.