Location: Violet City
Gym Leader: Falkner
Specialty: Flying-type
Reward: Zephyr Badge, TM31, Can use HM05 - Flash

Puzzle:
The first leader in Johto is the young Flying-type master. His gym has no puzzle to complete, and can be challenged as soon as you get to Violet City. However, it is recommended you train in Sprout Tower before taking on the gym challenge. The S-shaped gym hosts two trainers before Falkner, both of whom use the Flying-type birds Pidgey and Spearow that you meet early in the game. Falkner himself isn't that much of a challenge; Cyndaquil or Totodile can take them out quickly. If you chose the former, watch for their special move Mud-Slap, which deals Ground-type damage and lowers your Pokemon's accuracy. Chikorita will need to call in assistance from another Pokemon like Geodude or Onix, who can be caught in the Dark Cave or traded for in Violet City respectively. The prizes for this match are TM31 Mud Slap, the Zephyr Badge, the ability to use Flash outside of battle, and a slight boost in your Pokemon's Attack stat.

Location: Azalea Town
Gym Leader: Bugsy
Specialty: Bug-type
Reward: Insect Badge, TM49, Can use HM01 - Cut

Puzzle:
The gender ambiguous Bugsy is your next challenge in Azalea Town. Like in Violet City, there is no true gym puzzle - simply beat the trainers to get to the leader. The gym, of course, is packed with Bug-type users, and can only be accessed once Team Rocket is cleared out of the Slowpoke Well. Bugsy's first two Pokemon shouldn't be any trouble, as they have very weak attacks and low stats. Cyndaquil or a good Rock-type/Flying-type Pokemon can make quick work of them. Scyther, however, is a bit trickier. It will use the move Fury Cutter, which increases in power as it is used repeatedly. This can be very dangerous if you don't have a Pokemon who can resist it. Fortunately, since it is part Flying-type itself, a Flaaffy can best it with a strong Thundershock move. The prizes for besting the Bug-type trainee are TM49 Fury Cutter, the Hive Badge, the ability to use Cut outside of battle, and the full command of outsider Pokemon up to Level 30.

Location: Goldenrod City
Gym Leader: Whitney
Specialty: Normal-type
Reward: Plain Badge, TM45, Can use HM04 - Strength

Puzzle:
Goldenrod Gym's Clefairy maze shouldn't be that hard to navigate, although Whitney is a very frustrating Gym Leader in battle. Boasting the incredible Pokemon Miltank, the young lass will annoy you to no end with moves like Stomp, Metronome, Rollout, Mimic, Encore, and Milk Drink. Your best bet is to either use a Gastly you caught earlier in the game or trade for the Machop at the Department Store. Miltank's Attract can be very annoying, since it will more likely then not render your starter useless if it's of the male gender. Bayleef may actually come in handy here, as it resists Rollout. Rollout, like Fury Cutter, increases in damage as momentum is built, though it is much more powerful. If you beat Whitney, you'll receive TM45 Attract, a slight bump in the Speed of your Pokemon, the Plain Badge, and the ability to use Strength outside of battle. You will also be able to get the Squirtbottle in the flower shop next door to spray Sudowoodo with. Whitney will try and refuse to give you the badge at first, but if you talk to the trainer below her, you'll find out how to change her mind.

Location: Ecruteak City
Gym Leader: Morty
Specialty: Ghost-type
Reward: Fog Badge, TM30, Can use HM03 - Surf

Puzzle:
Morty's gym features the first true puzzle: there is a path in the dark field you must navigate or else you'll be sent back to the front. It might take some practice, but if you make sure to face every trainer you'll get it eventually. The trainers in the gym all use Ghost-type Pokemon, which can't be hit by Normal-type or Fighting-type moves. Conversely, they cannot hit Normal-type Pokemon. Use that to your advantage with a Noctowl or Togetic that can hit back with Flying-type or Psychic-type attacks. Alternatively, bring a Gastly of your own in to get the job done, or win an Abra at the Goldenrod City Game Corner. Morty is just more of the same; he has a Gastly, two Haunters, and a Gengar. Assuming you're using a Normal-type, the first three can only put you to sleep or try and Mimic your own attacks. They can also use Curse, which takes away half their health in exchange for removing a quarter of yours each turn. These can be used to your advantage by switching out, as long as they haven't locked you in with Mean Look. Gengar is a bit more tricky but anything with a strong Dark, Psychic, or Ground-type move can take it out. It will try and put you asleep with Hypnosis, then use Dream Eater to heal itself. Switch out if you can when it does this. Shadow Ball is kind of useless on it as it has terrible Attack. When you win, you receive TM34 Shadow Ball, the Fog Badge, the ability to use Surf outside of battle, and command of Pokemon up to Level 50. Go check out the Ecruteak Theatre now to try and get HM03 Surf.

Location: Cianwood City
Gym Leader: Chuck
Specialty: Fighting-type
Reward: Storm Badge, TM01, Can use HM02 - Fly

Puzzle:
Chuck's gym requires Strength, found in the Olivine City Cafe. Other than that there is no puzzle: just fight the trainers. They use Pokemon like Hitmonchan and Mankey and shouldn't be that hard if you have a Psychic, Flying, or Ghost-type. Chuck's Primeape can't even hit a Ghost-type, though watch for Poliwrath's Surf. A good Pokemon here would be Xatu, who double resists Fighting-type moves and can hit back with Psychic. Poliwrath likes to use Mind Reader then DynamicPunch, which always confuses you and deals massive damage. Again, a Ghost-type like Gengar would have nothing to fear. If you win, you'll get the Storm Badge, the use of Fly outside of battle (Chuck's wife gives you HM02), command of Pokemon up to Level 70, and TM01 DynamicPunch.

Location: Olivine City
Gym Leader: Jasmine
Specialty: Steel-type
Reward: Mineral Badge, TM23

Puzzle:
The gym is very straightforward, although you will need to bring Jasmine the Secretpotion from Cianwood Pharmacy at the top of the Glitter Lighthouse before she'll fight you. No trainers, just Jasmine. The former Rock-type user is proficient in Steel-types like Steelix, so bring a Fire-type. Quilava or Typhlosion works incredibly well here, and although Feraligatr might seem like a good choice too, it needs to watch out for Magnemite. Steelix will try to hit your Fire-type with a Rock Throw, though if you're faster you should be able to take it out in one hit. Growlithe, Flareon, or Magmar all do the job very well if you didn't start with Typhlosion, and a Sandslash can hit hard with Ground-type moves if its Attack is strong. Defeat Jasmine for TM23 Iron Tail, a boost in your Pokemon's Defense stat, and the Mineral Badge.

Location: Mahogany Town
Gym Leader: Pryce
Specialty: Ice-type
Reward: Glacier Badge, TM16, Can use HM06, Waterfall

Puzzle:
This gym has a very annoying ice sliding puzzle. Use the rocks as stopping points, fight the trainers, and navigate your way to Pryce. To battle the senior Ice-type master, use a Fire-type. Don't worry about Dewgong and Seel - they don't have any Water-type moves to extinguish you with. They can use Rest to heal all damage but will be unable to move for two turns so try and strike them then. If you have a good Water-type Piloswine will fall before STAB moves and can't hit very hard with its own. When defeated, Pryce will cough up the Glacier Badge, a boost in your Pokemon's Special Attack and Special Defense, the ability to use Whirlpool outside of battle, and TM16 Icy Wind.

Location: Blackthorn City
Gym Leader: Clair
Specialty: Dragon-type
Reward: Rising Badge, TM24, Can use HM07, Whirlpool

Puzzle:
The final gym. Lance's cousin is the hardest leader in the game. Her gym is no cakewalk either; you must fight several trainers and complete a puzzle involving Strength to build bridges across lava. Many trainers use Dratini or Horsea so bring a Pokemon who can wield Ice-type and Electric-type moves. Perhaps look for something that can learn the elemental punches. When you face Clair, you will need to use something that can survive Paralysis and has good Ice-type attacks. Luckily, you can catch a Swinub in the Ice Path and evolve it into the powerful Piloswine. Piloswine can take the Ice-type and Electric-type moves the first two Dragonair like to use, and hit with either Ice Beam or Icy Wind to lower Speed. The other Dragonair, however, has Surf, so watch out. Lanturn is also a great choice as it resists the three elemental moves the Dragonairs use. Kingdra is a very annoying Pokemon as its only weakness is Dragon-type. To beat it, try inflicting status on it and whittle its health down slowly. It's a very tricky Pokemon to defeat, especially because of Smokescreen. Upon defeating Clair, you'll have the first set of Gym Leaders under your belt. To get the badge, though, you must retrieve the Dragon's Fang from deep in the Dragon's Den. This requires the use of Surf and Whirlpool. Upon claiming the fang, Clair will bestow on you the Rising Badge, TM24 Dragonbreath, and the ability to use Pokemon of any level in battle. It is recommended you give TM24 to a Kingdra for use during the Champion battle. Now you are ready for the Pokemon League!

Location: Vermilion City
Gym Leader: Lt. Surge
Specialty: Electric-type
Reward: Thunder Badge

Puzzle:
The electrifying Lt. Surge is probably the first leader you'll meet in Kanto. You can use Cut or Surf to get to the gym. Lt. Surge's gym has an interesting novelty - you need to check for two switches hidden in the garbage cans to open the automatic doors. The second is always next to the first, be it the can north, south, east, or west, but will be difficult anyways to find as the locks reset if you click on the wrong can. The trainers are all fairly easy to beat, however you may need to heal a few times should your Pokemon become paralyzed. Surge has a new team with buffed up Electric-type moves like Zap Cannon and Thunderbolt. Zap Cannon, like DynamicPunch, has a low accuracy but high base damage, and will always cause a status ailment, in this case paralysis. Magneton will use Lock-On to make sure it hits. A Ground-type Pokemon like Nidoking or Steelix is great here as it can wipe the floor with the team and have very little used against it. The prize for this match is the Thunderbadge.

Location: Saffron City
Gym Leader: Sabrina
Specialty: Psychic-type
Reward: Marsh Badge

Puzzle:
Sabrina's gym is back with a network of teleporters. Have fun trying to navigate through this mess. Again, a hint - you will need to battle a few of the trainers, who use Psychic-types like Exeggcute. Sabrina has a new team this time, composed of Pokemon that are completely useless against Dark-types like Houndour and Umbreon. The infamous female Mr. Mime will try and set up reflects to aid her team mates, and Baton Pass any Barriers it has up in the process. Ghost-type Pokemon are great here, just like with Will. Defeat her for the Marsh Badge.

Location: Celadon City
Gym Leader: Erika
Specialty: Grass-type
Reward: Rainbow Badge, TM19

Puzzle:
The Celadon Gym is home to the nature-loving princess Erika. Bring a lot of Full Restores because of status moves the gym trainers like to inflict. Erika has a new lineup featuring Bellossom and Jumpluff. Instead of Mega Drain though, the move of choice is now Giga Drain, which does the same thing but with more damage. Her team likes to use Sunny Day to drench the field, which makes Solarbeam hit in one turn instead of two and Synthesis heal much more HP. However, this will also buff your Fire-type attacks which is fantastic. Defeat her for TM19 Giga Drain and the Rainbow Badge.

Location: Fuchsia City
Gym Leader: Janine
Specialty: Poison-type
Reward: Soul Badge, TM06

Puzzle:
With her father now a member of the Elite Four, Janine has taken over as the new leader of Fuchsia City's Pokemon Gym. She is also the weakest, and shouldn't be that hard to beat if Koga wasn't. The gym still uses the invisible walls, and this time everyone is dressed up like Janine, making her tricky to spot in a crowd. Psychic and Ground-type moves will be your greatest help here, though pretty much any neutral move gets the job done considering the levels of her Pokemon. Defeat Janine for the Soul Badge and TM06 Toxic.

Location: Cerulean City
Gym Leader: Misty
Specialty: Water-type
Reward: Cascade Badge

Puzzle:
To battle Misty, you'll have to go to Cerulean Cape just above the city and interrupt her date. Furious at this, she'll gladly battle you back at the gym. You can skip all the trainers by using Surf in the water, though they don't have very strong teams anyways. Meganium's time to shine is here, where it can sap health from everything using Giga Drain or slice up foes with Razor Leaf. Keep an eye on Lapras and Starmie though as they both use Ice-type moves. If you didn't pick Meganium, an Ampharos or Raichu also does great work here. Misty shouldn't be that hard making the Cascadebadge is an easy prize to win.

Location: Pewter City
Gym Leader: Brock
Specialty: Rock-type
Reward: Boulder Badge

Puzzle:
Brock's gym hasn't change in simplicity. Defeat the lone trainer then go up against the Rock-type master. He's evolved his Geodude, caught a Rhyhorn, and resurrected the two fossil Pokemon from the first games. Meganium works well here as its Grass-type moves do 4x super effective damage. Alternatively, try a Water-type for the first three and Electric-type moves for the fossils. Contrary to popular belief Electric-type moves do hit Rock-types so make full use of them. Brock will give you the Boulderbadge upon defeat.

Location: Seafoam Islands
Gym Leader: Blaine
Specialty: Fire-type
Reward: Volcano Badge

Puzzle:
Poor Blaine's gym was totalled in the Cinnabar Island volcanic eruption, and he's now stuck in the Seafoam Island cave. He's still insistent on the need for a Burn Heal, and with moves like Fire Punch, Flamethrower, and Fire Blast in his arsenal you better have one. Magmar has Thunderpunch to fight back against your Water-types, but the rest of his triad are sitting ducks. If you can't use a good Water-type for whatever reason, Rock and Ground-type moves are fantastic too. Defeat Blaine for the Volcano Badge and move onto Viridian City.

Location: Viridian City
Gym Leader: Blue
Specialty: None
Reward: Earth Badge

Puzzle:
Since Giovanni's departure, the gym has been under new management. However, this old foe will 'smell ya later' until you collect the other seven Kanto badges. This Lego-built gym doesn't have any puzzle and is a straight up challenge against Blue. He has a very diverse team and is probably just as tricky to beat as he was at the end of Red and Blue. With the classic core of Grass/Fire/Water, you should probably bring a Dragon-type if you can to resist their powerful moves. Alakazam has the very powerful Psychic but can be taken out by anything faster than it with a physical attack. Pidgeot can get zapped with Electric-type moves, stoned with Rock-type moves, or chilled with Ice-type moves. The latter of those can also be used for Rhydon, or with Grass-type and Water-type moves instead. Bring lots of potion and a well balanced team for this match and you shouldn't have too much issue. Win, and you'll get the Earth Badge, which gives you access to Mt. Silver after you talk to Professor Oak. There, the ultimate trainer awaits...