Editorial. The late professor Gen Matsumoto.

At the opening of this special issue dedicated to the work of the late Prof. Gen Matsumoto, I would like to look back at Gen Matsumoto's research life and to personally share with the readers of this journal his dream of creating a real brain-like computer. Gen Matsumoto had been planning to create a brain-like computer for thirty years. I have been most fortunate in being able to personally see progress toward Gen Matsumoto's ultimate goal, and have been inspired by his persistence, perseverance, and full belief that one day a brain-like computer would be operative. Gen Matsumoto left a definite impression on me so much, so that I considered him my reference of life rather than just my research partner.