Complex sentence: The Etsuzankai organization, led by prime minister Tanaka Kakuei, was highly influential in bringing infrastructure improvements to Niigata in the 1960s and 1970s, including the Joetsu Shinkansen high speed rail line and Kanetsu Expressway to Tokyo.
Split into simpler sentences: The Etsuzankai organization, led by the politician Tanaka Kakuei, was highly influential in bringing infrastructure improvements to Niigata Prefecture in the 1960s and 1970s. These included the Joetsu Shinkansen high speed rail line and the Kanetsu Expressway to Tokyo.