Mt. Takao was a popular hiking spot in Hachiōji (八王子) of Tokyo. The place was connected to Tokyo City Center by Keio Takao Line and JR Chuo Line. From Shinjuku, it takes about an hour to reach there. Due to the ease of access, most of the hiking trails in Mt. Takao was quite busy and crowded. That was not desired for butterfly watching. Instead of Mt. Takao, Kogesawa Woodland Trail (小下沢林道) in the region is a better site for butterfly watching. Right outside Takao JR station, there is a bus connecting to Kogesawa. The bus ride took just about 10 minutes.
Mt. Takao was known for “Tengu” (天狗), a legendary big nose creature in Japanese folk. I am not sure whether it is related or not, Libythea celtis (朴喙蝶) was so common in the region. The butterfly was also having a big “nose” so it was called called “Tengu” butterfly.
The vegetation looks suitable for butterfly watching. I was able to spot many butterflies deeper in the trail. Still, end May to early June was not yet the peak butterfly season there. I would expect seeing more butterflies in July and August.