Wait !! You are referring to full-fare tickets.
Japanese airline companies never sell domestic filight tickets earlier than two months before flight date (except for only a few special cases).
As discounted prices for Nov. have not been even filed yet, you can find only full-fare now.

If your planned flight HND-OKA is, for example, 01 Nov., try to book your flight at 9:30 a.m. (JPN-time) on 01 Sep. via the ANA, JAL or SkyMark website. Normally you will be able to find oneway HND-OKA in USD 125-175 range for Nov.

But please be aware in advance that Monday 23 Nov. is a public holiday, consequently, discounted tickets from HND to OKA on 20/21 Nov. and OKA to HND on 23/24 may be quickly sold out. So you should not forget date and time of booking.