While removing opponent's ability to castle in the future. 

 You ever play on jester?  I feel like there are enough chess people here to get some fun games going. 

 I have played on Jaster sometimes; it's a great app. I should probably become more regular there. 

 Yeah, me too!  I'm not about to enter my neec though. Maybe it can be forked and add nos2x, ally, etc.. 

 We loved this move, when we were kids.