There is a larger picture, however, that helps us better understand how systems should be defined. For example, Koryu (ancient) systems have (i) a history and traditions; (ii) a lineage of headmasters or grand masters; (iii) are internally consistent; (iv) have principles that cohere and work together in the application of strategy , technique and generation of power; (v) have specific combat strategies (Heiho) that work together with a system's principles; (vi) have a guiding philosophy and an ethical code of conduct, and (vii) have a system for teaching and transmitting their deeper levels of knowledge (through Shoden, Chuden and Okuden forms) that is uniquely Japanese. So, a system is clearly much more than its list of techniques. Examples of Koryu systems include Takenouchi Ryu (1532), Segikuchi Ryu (1630), Tagaki Ryu (1645), and Tenshin Shinyo Ryu (1830), among others.
Therefore, what helps differentiate Japanese Jujutsu from other arts from China, Korea or even western pugilist arts, for example, is not the sum total of its techniques, for techniques alone do not make a system. It is the way items (i) through (vii) above are integrated, practiced, and passed on that helps differentiate different systems and their origins.
A noteworthy evolution of these Koryu systems after the Meiji Restoration of 1868 is the emergence and development of Gendai (modern) systems. Many such Gendai systems originated in Japan (although not all) , and while they are often grounded in, or influenced by Japanese Koryu systems, their modern versions reflect a larger array of goals and practices. Examples include the addition of such goals as personal growth and development and other broader educational goals. Thus, after the Meiji Restoration we begin to see the transformation of Jujutsu from a strictly Bujutsu art to Budo with an emphasis placed on the study of the "Way". Granted, many Koryu systems retained their original emphasis on battlefield combat but today most are extinct. The few original systems that remain to the present day have reinvented themselves from purely Bujutsu to Budo arts. Such systems (of more recent origin) often reflect a blending of influences from multiple Koryu systems and traditions, and their lineage and origins suggest this multiple form of parentage. Judo, for example, derives primarily from Tenshin Shinyo Ryu and Kito Ryu while Aikido originates primarily from Daito Ryu Aiki Jujutsu. I say primarily because the founders of many such Gendai systems studied several jujutsu arts and were influenced by many teachers from different systems.
Finally, and NOT to deny the fact that cross fertilization from other cultures often influences the development of a system, there is no question that Chinese martial arts, and aspects of Chinese philosophy have had a role to play in the development of Japanese Jujutsu. After all, even the Kanji the Japanese use are of Chinese origin. However, this only speaks to the fact that knowledge does not grow and develop in a vacuum but is also influenced by ideas from other cultures. This does not make Jujutsu a Chinese art, however, for while the Japanese were clearly influenced by China, the fighting systems they developed, and the way they were reworked, reinvented, integrated, blended and handed down is what makes Jujutsu a uniquely Japanese art.