The CBS name was required for international operations, excluding Japan, primarily due to branding and trademark reasons. CBS (Columbia Broadcasting System) had established a strong brand identity and recognition in the global market, which was crucial for their international ventures.

In Japan, CBS had a different operational strategy and branding approach, leading them to operate under a separate name that resonated more with the local market. This was likely due to cultural differences, existing market competition, and the need for a more localized brand presence.

For more detailed historical context, you may refer to articles discussing CBS's international operations and branding strategies.