As functional art the katana exists in two worlds, that of the martial artist, and that of the collector. Katana are defined by their dimensions, yet, never before has the katana been approached analytically. Here, for the first time, Dr. Andresen uses a data driven approach to make the katana more accessible to martial artists and collectors alike. The swords used by iaido practitioners, bokuto, iaito, and shinken are deeply analyzed with scientific rigor. Bokuto are dissected down to the species of wood used to make them, iaito are considered from a risk perspective, and shinken are summarized and analyzed statistically. Regarding bokuto Japanese and Western woods are discussed in addition to bokuto construction. Likewise, every dimension of shinken is evaluated by historical era and bohi status. Among other important findings the data suggest that Heisei era katana are divergent from historical norms. In addition, various models are presented that can predict unknown katana dimensions but especially blade weight, which is of concern to iaido practitioners. Even the traditional methods of sword care are reconsidered in favor of superior modern techniques. It is hoped that the data discussed in this work helps iaidoka better understand the katana and thereby the martial art they study. Collectors, scholars, and craftsmen can also benefit from Dr. Andresen’s unique approach to the katana.