Osaka > Fukuoka Train Tickets

I have a question about buying tickets (round trip) To/From Osaka - Fukuoka.

I will be traveling to Japan in January for a concert and will be leaving from Osaka to Fukuoka. However, I'm only arriving 2 days before the show.

I asked someone & they said I need to buy train tickets from O - F over a month in advance if I want to get seats. Is this true?

There's no way (that I know of) that I can get tickets that early & I am relying on buying them when I arrive. Can this be dispelled/confirmed? If it is so, is there anything I can do to get tickets in advance? Thanks!

I asked someone & they said I need to buy train tickets from O - F over a month in advance if I want to get seats. Is this true?

No, not at all! It is not even possible to make seat reservation for trains more than one months in advance.

You have several ways of travel as outlined below. Tickets for most of them can be bought on the day of travel. On trains, in particular, there are unreserved seats, which do not require advance reservation, at all:
http://www.japan-guide.com/e/e4802.html?aFROM=2157_2161

If you prefer to fly, you can easily make reservations in advance from outside of Japan.

Including the fare from the airport to Shin Osaka, by Hikari with reserved seat is 15,840 Yen and by Nozomi is 16,140 Yen. If you are just there as a tourist and will complete your round trip to Fukuoka within 7 days , you would be financially better off getting a 7 Day JR Rail Pass:

http://www.japanrailpass.net/

If you then use the Hikari Rail Star service, a reserved seat is almost like Green Car (first class). The only disadvantage is that, due to service cutbacks, there is now only about one Hikari per hour, previously it was about every 30 minutes.

Hello. If you only want to travel between Osaka and Fukuoka, you can use Sanyo Area Pass. It costs 20000yen for 4days and now, you can make seat reservation if you reserve it online. Japan Rail Pass is 28400yen for 7days(this is not good for you...). I think if you want to make seat reservation, this website is very useful.
And if you use Kansai international airport, you can upgrade to 1st class car of Kansai airport express Haruka as online reservation benefit!
http://www.jr-odekake.net/en/jwrp/index.html