A two-way chipper, or jigger, is a utility golf club with two lofted striking faces. It can be used right or left-handed and is useful around the green and also for negotiating obstacles on other parts of the course.
A two-way chipper can be used during "social" play, if all the players agree to its use, but is illegal in any form of official tournament play. Essentially, players need to learn to use a high-angled wedge or putter in place of a two-way chipper for tournament play.
Rule 1-3 of the Rules of Golf states that players cannot agree to waive any rule of golf, so even if the use of a two-way chipper is agreed to during tournament play, the offending players are liable to disqualification.
Appendix II of the Rules of Golf states that the clubhead of any golf club, other than a putter, must have only one striking face. Appendix II also states that a putter is a club with less than 10 degrees of loft, so a two-way chipper cannot be classified as a putter.