There is a combined area called the Joetsu-Koshinetsu region 上・甲信越 which includes Niigata, Nagano and Yamanashi prefectures and sort of takes up a long narrow area of central Japan. It looks sort of strange, but it is frequently thought of as belonging together. A good example is this blueberry cheese cake-white chocolate KitKat is limited to sales in that region. ネスレ キットカット ブルーベリーチーズケーキ Nestle
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