The NPB's three-and-a-half hour rule was repealed during an executive committee meeting today.
The rule was implemented in 2011 out of energy consumption concerns after the Tohoku Earthquake. It was carried over into the 2012 season, but Central League officials felt it was not creating a large enough difference in game times to keep it going for this season.
Source: Daily Sports 3/7/2013
UPDATE @ 10:16pm - The rule was apparently repealed because the NPB felt the increase in tie games was turning fans off. The rule will be reconsidered if energy consumption issues become a problem again. Otherwise, the NPB confirmed that teams and stadiums will continue to do their part to help conserve energy; and players, managers, coaches, and umpires will continue to do their best to keep games moving along as quickly as possible.
Source: Sanspo 3/7/2013