Spring training is getting underway in the US and Japan, so now is a good time to talk about the last game I saw last year. It wasn't an NPB game, though - I headed to a not-too-small stadium in Kanagawa prefecture to see the Japanese Women's Baseball League play another double header. This was my second visit. You can read about my first trip here.
website (Japanese only) seems to indicate that there will be events on April 11th and 18th, but I can't tell where yet. But, then, those are Fridays so I won't be able to attend. They do several events over the year and I'm sure they'll announce a bigger schedule later on!