The original U.S. TV series "CSI (Crime Scene Investigation)," set in Las Vegas, has been so successful that it has almost grown into a franchise, with "CSI: Miami," "CSI: NY," and "CSI: Triology." After visiting the "Ryoma Den" exhibition at the Edo-Tokyo Museum, which looks at the life of the 19th-century samurai and reformer Sakamoto Ryoma, I almost felt as if there had been yet another spinoff — "CSI: Edo Japan": So much of the exhibition details the grisly circumstances of its subject's assassination, including a full-scale reconstruction of the actual room in which the deed happened.

But perhaps like James Dean or Che Guevara, the way Sakamoto died is the key to the way he is remembered — and remembered he most certainly is as the subject of NHK's latest historical drama "Ryoma Den." In fact, this exhibition is being run in conjunction with that TV series.

Since his death in 1867, at the age of 33, Sakamoto has become a national icon and a symbol of the Meiji revolution that toppled the Tokugawa shogunate and opened the way for Japan's modernization. This is surprising because, even though he was undoubtedly in the thick of the action, he was essentially a lower-ranking samurai, who died before he could realize his full potential and who never held an important office.