It is possible to sell. You have to send mona to your monatr.jp wallet to sell.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fmilk.tea.jp%2Fi%2FWHqBJb.png&t=665&c=63OSXPHvbU5__g)
Left side: Buy BTC by selling Mona
Right side: Sell BTC to buy Mona
1: Total Mona you need to put in your buy order
3: How much BTC you want to buy
2: How much BTC you want to sell
4: Total Mona you'll receive with your sell order
The whitened out areas below the table elements show you how much Mona/BTC you currently have in your monatr.jp wallets.
My wording might take a bit of wrapping around your head before it clicks, but I hope it helps.
edit: i just realised I reiterated exactly what was in led_lcd's article. gg
Why can't i trade Mona/BTC? I only sell and buy BTC/Mona