Premise: Cross Gene (Korean: 크로스진; stylized as CROSS GENE) is a five-member boy group based in South Korea. Signed under Amuse Korea, the group consists of South Korean members: Shin, Sangmin, Yongseok and Seyoung and Japanese member Takuya. They released their debut mini-album "Timeless: Begins" in 2012, which peaked at #8 on the Gaon weekly album chart.
Hypothesis: If Takuya left Cross Gene without being replaced, Japan would no longer be represented.