My interest in bioinformatics began with a computer programming class which I joined as an undergraduate in biochemistry. I was deeply attracted to doing programming, even with now incredibly poor computer environment, such as a slow CPU, a small amount of memory and a line editor. Finishing the BS degree in Biochemistry and Biophysics, I embarked upon a graduate course of computer sciences to satisfy my interest in computers and software. After completing the ME degree in information engineering, I went in with the Machine Learning group of NEC Research Laboratories in Japan. In NEC I devoted myself to doing research on machine learning and data mining, developing new techniques in these fields as well as considering a lot of modern, real-world problems like telecom churn, campaign management, web access pattern mining and sequence analysis in bioinformatics. I received PhD (Doctor of Sciences) in information sciences in the area of machine learning and bioinformatics, while working with NEC. I then moved to Institute for Chemical Research (ICR) in Kyoto University to focus more on biological applications and have built data mining techniques for solving problems in life sciences, paritcularly those over graphs and networks, such as gene networks, medical pathways and molecular structures. I am currently a professor of the Bioinformatics Center of ICR, being jointly appointed as a faculty of the School of Pharmaceutical Sciences of the same university.