There isn't much material about Renju in Spanish or English. I mostly use the apps Gomoku xxxx and Gomoku xxxx, which I find very good. I enjoy the online aspect of Gomoku xxxx and the puzzles on Gomoku xxxx, but I feel like I need more to truly improve. 

I'm also wondering if there are any professionals who speak English (or Spanish) and offer Renju classes.  Thank you!