
After the US attack on Rabaul harbour on the 2nd November a new threat developed for the landings on Bougainville. The Japanese had been careful to avoid exposing their ships to undue risk, but they now felt compelled to bring in a force of seven heavy cruisers, one light cruiser and three destroyers. They were spotted refuelling in Rabaul, and it was obvious they were set for an attack on the ships off Bougainville.

The U.S. had no capital ships near enough that would be able to challenge a force of this strength. For Admiral William 'Bull' Halsey it was:
the most desperate emergency that confronted me in my entire term as ComSoPac.


