Understanding local electrochemical reactivity of surfaces is crucial for electrode design and applications at device level, in the fields of energy storage, biosensing, or electrocatalysis. In this work, we attempt to optically map the local electrochemical reactivity of surfaces not by "looking" at the working electrode (WE), but by measuring optical change of the counter electrode (CE). The concept is based on an electrochromic CE that changes color with electron transfer accompanying ion intercalation. As the CE is placed in parallel with the WE and maintains a micrometer range distance, the optical transmittance of CE reduces locally at positions corresponding to the active area of WE when applying a suitable anodic potential. The change can be captured dynamically in the form of video, which offers information on the transient behavior of the system. The spatial resolution of CE imaging increases as the distance between WE and CE decreases, likely due to the de-homogenization of current distribution on CE. The reported method offers a label-free alternative for measuring "invisible" electrochemical reactions, that is to say, does not require to modify neither the WE nor the electrolyte.