Board Thread:Theories and Speculation/@comment-36512555-20200202084241/@comment-32685487-20200205205705

There are things in the series. He uses Sensory abilities to find them from within Kamui. He's always done that. Sasuke asks him "how did you find me" and he tells Sasuke that its within his power. Itachi referred to Sensory abilities in a similar way when saying Nagato had that power. Obito is clearly a sensor type.