Board Thread:Theories and Speculation/@comment-34661853-20181111160651/@comment-32685487-20190109011211

The connection they shared was through the powers he gave them, SPSM and the Tomoe Rinnegan. They have there own Six Paths chakra, but somehow through those powers they each can sense each other. Naruto needed SPSM to sense Sasuke and that was the proof.