This book explains with many examples and self-practices with answers to how to bid. Opening the auction at level 3 and even at level 4 are intended, among other things, to interfere the opponents to reach their best fit. On the other hand, they may be a boomerang against you and your partner if you are not careful to calculate the number of your safe tricks given the vulnerability. It's a good feeling to enrich your bridge game and that of your partner with this conviction and surprise your friends around the bridge table and increase the partnership communication. Thanks again for downloading this book, I hope you enjoy it!