The two Tone-class cruisers provided reconnaissance for the carrier force. Avoiding discovery required finding other ships before those ships could report the formation. The northern approach reduced exposure to the main trade routes and their larger, more modern merchant vessels. Radio-equipped merchants still presented a danger even away from those routes.
Notable Point · 1:06:38-1:07:14
Tone-class reconnaissance protected the carrier force's secrecy
Reconnaissance helped the carriers find and avoid other ships before those ships could report them.