JK-FLOW (Japan-Korea Fluid Mechanics Online Workshop) is an online seminar series on a wide range of topics in fluid mechanics. By taking advantage of the fact that both JK communities are in the same time zone, we aim to build a platform promoting discussions and potential collaborations worldwide. We particularly encourage scientific discussion with a focus on early-stage researchers. The target area in this online workshop includes: unsteady fluid dynamics, flow control, turbulence, fluid-structure interactions, heat transfer, experimental diagnostics, modal analyses, data-driven analyses, reduced-complexity modeling, and control and dynamical systems, but not limited to the above.