Stop straining to "see" Krishna during japa. Reverse the direction of the gaze. Know this: it is Krishna who sees you, His eyes are already on you. Remember how you can feel someone's gaze on your back — you don't see who is looking, but you know for certain you're being watched. It's like that. And if He casts His kṛpā-dṛṣṭi, His merciful glance, upon you — it is that very glance that will one day give you the power to see Him.