My acquaintance with Chris dates back to perhaps the fall of 1976 when he was invited to the Center for Mathematical System Theory in University of Florida, which Professor Rudolf Kalman established and was directing. When he came, he was a young faculty at the University of Arizona (I think), and gave some talks on delay systems, controllability or so, I believe, but I don’t trust my memory very much on this. Anyhow, he gave a couple of seminars then, and later again (maybe in 1977), he came to Florida.

As we all remember, Chris has his irreistible charm and humor, and he soon became very popular in the Math department of Florida. I had spent a lot of time (looks like he must have spent several weeks in Gainesville) with him, particularly weekends, and it was our standard practice to go to a beer bar on weekends near the Florida Bookstore which was across the University Library.

We talked about a lot of things, partly mathematics, system theory, but perhaps mostly about daily casual things and nonsensical jokes etc., which often encouraged me a lot, who was just about to finish his Ph. D. study. This gave me a lot of moral support.

After that I met Chris in many conferences, but above all Chris played a decisive role in pulling me into the MTNS steering committee, and also supporting me for bringing MTNS conference to Kyoto. The conference held in 2006, I pride myself in, turned out to be a great success. Part of the regret is that Chris could not attend this conference due to his eye surgery.

Chris visited Kyoto a couple of times, in which we always had fun to- gether. He loves good food (for which Kyoto is famous), good wines, good sake, and above all, good life, as well as enthusiasm toward research. Chris always amazed me for how much he knows about mathematics, and also en- gineering. Our research fields were somewhat a bit disjoint, so I only regret that I did not have a chance to write a joint research with him.

The last time I talked with Chris was during the CDC conference in Shanghai, December 2009. He appeared to be very tired, and I was a bit concerned, but little did I know then that I was not going to see him again. I was actually expecting to see him again in March in Kyoto this year for my 60th year birthday. Never did I dream that this had to become impossible in such a sad way. I wish him, as Japanese always say, happiness in an- other world, where he can enjoy as much Brunello di Montalcino or Sassicaia without restraint.

Chris, we miss you very much and send you best wishes, along with 8 million Shinto gods of Japan.