Wait a minute: How many opening days are there?

First, there was last week in Japan. (BTW, how does Japan rate hosting the opening opening day every year? What about Mexico, Venezuela, Puerto Rico or the D.R.? Nothing against Japan here, but what have they done for us lately? Yu Darvish? Gimmie a break.) 

Then there's yesterday's Opening Day, the non-official official opening day.  Then there today's secondary, for many teams, opening day. And tomorrow, the Yankees and Rays, and the rest of baseball, open with the post-secondary Opening Day. Of course, next week, the Yankees hold their home opening day.

Yeesh. This is like the NBA playoffs: they start in April and end in July.