Now on to the tutorial. Method 1 is the simplest way without installing an app. However, if your network is filtering L2TP/IPsec packets or you'd like the simplest way and you don't mind installing an app, method 2 will work for you (below). If you have an iphone, click here for instructions without an app (Method 1) or click here for instructions using the OpenVPN Connect app (Method 2). This will simply give you a Japanese IP address. I heard iphone users need a separate itunes account as well, but I can't really help you download and install Mercari through itunes.
Method 1: No separate app required