We daily double-click the icons to open the files or to exert the program: this is clearly distinguished from the single click, which is often for selecting or highlighting the program. This year, iGEM CHIBA is constructing genetic double-click system whose output is released only when the input (inducing agent) is given twice within a limited time. To discriminate double-click from two separated single-clicks, the 1st input is to be memorized temporarily. If the 2nd input is added before the memory gets lost, output will be produced. If the 2nd input is not added within the given time, the system will be reset to the original state. This mechanism could work as a sort of safety device; by requiring the 2nd ‘confirmation’ input, one can drastically reduce, or even eliminate, the frequency of false-inputs. This system could be useful in operating the potent or potentially-hazardous biochemical processes.