* Komatsu falls on Caterpillar's downbeat forecast
* Mining sector worst performer
TOKYO, Oct 26 (Reuters) - Japan's Nikkei share average edged down on Wednesday morning after U.S. stocks weakened on dismal earnings in the corporate sector while falling oil prices hurt mining stocks.
The Nikkei dropped 0.3 percent to 17,309.53 in midmorning trade, after rising to a six-month high on the previous day.
Japanese stocks had been recovering since the beginning of this month after oil prices started rising and the dollar began...