The Metal Gear Solid series is like the Olympics, according to series creator Hideo Kojima.
"When asked what the MGS series is to you, I once responded, 'It's like the Olympics.' A big event held every three or four years. You devote your life to the major goal of a fight on the world stage. You think of nothing beyond that. The latter half becomes difficult, and you think that you'll retire after this. But after release, you think about the next tournament," tweeted Kojima.
The next Metal Gear game due for release is Metal Gear Rising, a hack 'n' slash spin-off set for February 2013.
Metal Gear Solid 4 released in June 2008, more than four years ago, but Metal Gear Solid: Peace Walker arrived in 2010 on the PSP. A new game every three to four years suggests a new game in the MGS series will arrive in 2013 or 2014.