In the 1960s, what was notable in Shimano’s product development was the diversification of products in addition to the technical aspects. This was a time when the trend toward market segmentation and product diversification was growing also in industries other than the bicycle industry in Japan. Shimano, ahead of its competitors, increased its product range, including by bicycle type, by target, by function and by design. As one of them, Shimano took on the challenge of developing an unprecedented product: a shifting mechanism that combined an internal geared hub and a derailleur. In 1966, Shimano announced COMBI 12, a combination of a 4-speed derailleur and an internal 3-speed geared hub featuring an index system in the shifting lever. This enabled the rider to shift to the ideal gear ratio according to terrain at any time. The system that allowed precise gear shifting with the derailleur while making a light clicking sound led to later development of the Shimano Index System (SIS), which was adopted in the DURA-ACE 7400 series.