In Europe and North America, the PlayStation 4 has been available for pre-order for quite some time now. In Japan, it was only made available for pre-order three days ago.
As anticipated, because Japanese gamers have been waiting, stock on Amazon has almost gone in that period of time. However, the same can't be said for the PS4's library of games.
While many of the launch titles are very Western, Yakuza Ishin and Dynasty Warriors 8: Xtreme Legends aren't selling that well. Yakuza Ishin is ranked 41st in Amazon's top charts, while Dynasty Warriors 8 Xtreme Legends is ranking 191st.
Still, there is plenty of time for this to change, as the PS4 doesn't release in Japan until the 22nd of February, 2014. Many Japanese gamers likely just pre-ordered their console now, while taking more time to decide what games they want to accompany it.