question about rules.

[R. Carden]

During competition, may one switch from using the right hand to using the left hand, or vice versa?

[R. Carden]

Please someone answer this because I am wondering if I am wasting my time practicing Rock Paper Scissors with both of my hands.

[R Cohrs]

Probably not still around, but playing switch hand can be a bit tricky.  I'd say as long as you're opponent is aware of your intent.  For example, the famed and nefarious Midnight Rider likes to use his non-playing hand as a distraction, so it better be clear which hand is meant to count.  I play switch frequently, and I make it clear through body language which hand is going to be dominant.  If you line up your prime with your opponent, then it's easy to tell.

[wicked fingers]

Yes, you can switch hands during competition.  This was the strategy in my sweet 16 match in the US competition (Master Rosh can attest to) where after losing round 1 I went from throwing right-handed to throwing left-handed.

[martinburley]

Switching hands between throws is generally acceptable.

Switching hands during a throw (priming with one hand, delivering with the other) is generally not acceptable. In particular, the Official Rules for WRPSS-sanctioned tournaments forbid switching mid-throw:

4.0 Once the fist has reached the highest point of the final throw of the last prime, the delivery of the throw is considered to be "in approach". At any time during the approach of this final prime, the hand may be released in any of the following manners:

However, not all tournaments are run with WRPSS rules or WRPSS-standard refereeing, so switching hands mid-throw can be a useful tactic in those lesser tournaments (particularly when playing against someone familiar with WRPSS-sanctioned rules only). And it's regularly seen in Street RPS circles.