First gym leader in Kanto

The fist gym leader is in Pewter city. The gym leader use rock type Pokemon. The gym leader has 2 rock type Pokemon.They are called Onix and Geoduge. It is best to use water,or grass type Pokemon. Do not use fire or electric type Pokemon. The gym leaders Pokemon will be between levels 10-15. If your Pokemon is weak against the gym leader train your Pokemon to a high level. Make shire your Pokemon is not too high of a level because it may not start listening to you. So that was information you need to know about the first gym leader.