While most of post-tsunami studies focus on tsunami inundation heights, this study mainly focuses on inundating tsunami flow, which may have more direct impact on damages of the inundated area. Based on tilted poles and trees in the inundated area, this study collected data of tsunami flow directions at Rikuzen-takata, Ootsuchi, and Naraha. Obtained data totaled more than 850. Numerical tsunami inundation model was then applied to each of these sites to link simulated time-varying flow patterns with observed flow directions, which may represent the direction at which the largest force acted at each location. Proposed methodology is useful to deepen our understandings on the dynamics of the inundation tsunami flow.