As for my main goal of learning from "real world" situations in 3rd grade of leading program, I have applied for a 2-month fieldwork permit at OMRON cooperation, where having national-wide big data of home blood pressure measurement. Most of my time in the first month was for getting familiar with R software and the database named WELLNESSLINK for developing a research topic. The graduate course in Shiga University of Medical Science had provided me a firm knowledge background and necessary skills so that I could soon establish a dataset for analyses and successfully achieved main results within very limited time of fieldwork. I was really excited to explore the real-world data in OMRON for accessing seasonal changing of day-to-day blood pressure variability. This was also my first time working in a professional industrial environment in Japan. Having this valued opportunity, first of all, I would like to express my sincere gratitude to Professor Nakajima, Professor Miura and Professor Fujiyoshi as well as all of the staffs in OMRON Healthcare research team for their constant support and supervision.