Well:
"When the players got stronger they found that playing with "completely free" rules was in great favour of Black (the beginner of the game). It is also proved that there is a sure win for Black when playing with "completely free" rules."
(from http://www.renju.nu/r1rulhis.htm)
The rule "no-more-then-five for black" is one of "black" restrictions in renju.
Yes, I understand that, all I'm saying is I've never had trouble winning with 6 in-a-roll and yes it is alot easier to win in the very beginning of the game than it is in the middle or at the end. If the game goes on too long, its harder to win and the game drags on, but I guess thats what you get for not winning in the first place. LOL