I have never heard of that exchange before, but it's great to see that there is plenty demand for people to trade Bitcoin in Japan. I am trying to look at some kind of real time trading data to see how they are doing, but nothing shows up on the internet.
Yes, in the big scheme of things they are fairly new but they are showing positive signs of growth. And so is Japan, which seems to be hub of bitcoin news lately.
They do have an API where you can see trade history here
https://api.zaif.jp/api/1/trades/btc_jpy