Pinsir is most common in the Center Area of the Safari Zone, though it is also available in Area 1. It can also be purchased in the Celadon Game Corner for 2,500 coins. It is a LeafGreen exclusive and cannot be found in FireRed.
Pinsir is a rather unique Pokémon. It is one of the extremely uncommon fully evolved pure Bug-types, has no Bug STAB whatsoever, and still manages to be the best of the lot, beating even the likes of Compoundeyes Sleep Powder Butterfree with its raw stats. Pinsir's Attack is amazing, and its physical bulk is remarkable too; it will not fall to just about any special hit, either. It is a good addition in most teams where the physical presence is either absent or lacking. While Pinsir's damage output will generally not be as good as Fighting or Rock STAB, it can cover both of those roles effectively and be a welcome element of novelty for a nuzlocker.
Gym #3 - Lt. Surge (Vermilion City, Electric-type): If this fight had to be delayed for whatever reason, Pinsir is the 'mon for the job. Teach it Dig - more Dig TMs can be bought in the Celadon Dept. Store, if the free one was already used - and kill everything.
Rival (Pokémon Tower): Pidgeotto is not a threat; it can be 2HKOed with Rock Slide, or even OHKOed if Pinsir's level is higher. Kadabra 3HKOs with Confusion at best, and can be OHKOed by any physical move as strong as Rock Slide or stronger, with high probability (not guaranteed). Return dispatches Exeggcute and Ivysaur in two hits, if Pinsir's friendship is already maxed out; otherwise, it will only be a 3HKO at best. Return also 3HKOs Wartortle. Pinsir can also OHKO Growlithe with Rock Slide and 2HKO Gyarados and Charmeleon, though Charmeleon's Ember is close to a 2HKO, so a Rock Slide miss may endanger Pinsir if already damaged.
Giovanni (Rocket Hideout, Ground-type): Brick Break 2HKOs Onix and Rhyhorn and 2-3HKOs Kangaskhan. Whether or not the 2HKO will be netted against the latter is relevant, as Pinsir is not guaranteed to outspeed it - Kangaskhan's base Speed is slightly higher - and while its Mega Punch is outdamaged, it still manages to KO in two more turns after using Fake Out. Caution is advised against Giovanni's ace.
Gym #4 - Erika (Celadon City, Grass-type): Return 3HKOs all of Erika's Pokémon. Secret Power can get the job done, as well, but it will take several turns more, and Erika's Pokémon love inflicting status ailments; it is better for Pinsir to dispatch them as soon as possible, to avoid unnecessary delays and annoyances.
Gym #5 - Koga (Fuchsia City, Poison-type): Return 2HKOs both of the Koffing cleanly, leaving them just above healing or Selfdestruct range. Pinsir may eventually win the face-off against Weezing too, as its Sludge is close to Return in damage output, but Weezing will be much more annoying, poisoning Pinsir with Toxic and lowering its accuracy with SmokeScreen; Pinsir may still win, but it will likely take time and some healing items. The fight against Muk is a lost cause, it will spam Minimize and Acid Armor until Pinsir can barely scratch it.
Fighting Dojo (Saffron City, Fighting-type): Pinsir's Fighting resistance is very useful in this fight. Return will 2HKO Hitmonlee and its Hi Jump Kick does little damage. Return also 3HKOs Hitmonchan, whose Fire Punch is barely a 4HKO, due to its poor Special Attack.
Rival (Silph Co.): Rock Slide still 2HKOs Pidgeot, and its Aerial Ace is a 3HKO. It also OHKOs Growlithe, and Return 2HKOs Exeggcute; Gyarados can be 2HKOed with Rock Slide, as well, though Pinsir will need to watch its HP for Dragon Rage damage. Alakazam is 2HKOed by Return regardless of whether it uses Reflect or not; it will only become a 3HKO if Reflect is put up on the very first turn Pinsir battles it, and Pinsir is outsped. Defeating Venusaur is a struggle: Leech Seed and PoisonPowder combined make the 3HKO Return painful to score; Blastoise is only 4HKOed, but on the upside, its Water Gun is even weaker and it has no status tricks up its sleeve. Charizard should not be attempted: while Rock Slide does OHKO it, it will most likely outspeed and its Flamethrower is murder.
Giovanni (Silph Co., Ground-type): Nidorino is 2HKOed by Dig or Return, and Kangaskhan by Brick Break. Dig 3HKOs Nidoqueen as well, though Return only 4HKOs it; even with Return, Pinsir can still win the matchup, as it is faster and deals more damage than Nidoqueen's best move, Body Slam. Avoid Rhyhorn, it knows Rock Blast and can kill with a five-hit draw.
Gym #6 - Sabrina (Saffron City, Psychic-type): Pinsir can reasonably hope to outspeed Kadabra with a Speed-boosting nature or, at worst, take a hit from it and then knock it out with Return, since its best move is Psybeam. Mr. Mime is also 2HKOed by Return. Venomoth can annoy Pinsir with Supersonic, but other than that it doesn't have much to threaten the beetle with, since Gust has a low damage output; Rock Slide also 2HKOs it, with a small OHKO chance. Alakazam's Psychic, however, has the same damage output as Return, except Alakazam's Speed is much higher; Pinsir cannot win against it.
Gym #7 - Blaine (Cinnabar Island, Fire-type): Pinsir can OHKO Growlithe and Ponyta with Rock Slide, and at worst, take a Fire Blast from either of them if Rock Slide misses once. Both Rapidash and Arcanine, however, completely destroy it.
Gym #8 - Giovanni (Viridian City, Ground-type): Avoid fighting both of the Rhyhorn; they have Rock Blast, and that can easily dispose of Pinsir. Other than that, its resistance to Ground and good Attack and Defense make it a good counter for Giovanni; it can set up a Swords Dance or two in front of Dugtrio, Nidoqueen or Nidoking invariantly, and then proceed to OHKO the rest. At +4 Attack, Brick Break can even OHKO the other Rhyhorn, if it has not been defeated yet.
Rival (Route 22, pre-Elite Four): Pidgeot can be 2HKOed with Rock Slide unless it uses FeatherDance, which Pinsir can compensate with Swords Dance; its Flying STAB is still only a 3HKO. Rock Slide also easily beats Growlithe. Exeggcute is excellent for setups, as its only damaging move is SolarBeam, very weak against Pinsir; at +2 in Attack, after a single Swords Dance use, Brick Break OHKOs Rhyhorn and Return OHKOs Alakazam, both of which have strong moves that would have otherwise made Pinsir lose against them. Swords Dance also allows the Rock Slide OHKO against Gyarados, otherwise a 2HKO. Venusaur is 3HKOed by Return, or 2HKOed after a Swords Dance; Blastoise is also 2HKOed only after one boost, and 3-4HKOed without: using Swords Dance is recommended, especially as Blastoise can otherwise boost its Water Gun damage output with Rain Dance and become deceptively strong. Charizard still kills Pinsir no matter what; avoid it.
Elite Four Lorelei (Indigo Plateau, Ice-type): A Swords Dance against Dewgong allows Pinsir to OHKO all but Slowbro with Rock Slide. Slowbro can be 2HKOed with Return, instead, or OHKOed starting at +4 in Attack.
Elite Four Bruno (Indigo Plateau, Fighting-type): Pinsir can Swords Dance against Onix twice, as its Rock Tomb has low damage output. This allows it to OHKO the two Onix with Brick Break; Hitmonlee, Hitmonchan and Machamp are OHKOed by Return instead. Never fight Hitmonchan below +2 Attack, otherwise its Counter will kill Pinsir.
Elite Four Agatha (Indigo Plateau, Poison-type): While two Swords Dances are enough to OHKO all of Agatha's team with either Rock Slide or (for Arbok) Return, Pinsir is not in luck trying to set up against Gengar, which can poison and confuse it with Toxic and Confuse Ray respectively; it can also boost its evasion with Double Team. A persistent Pinsir backed by a PP restorative will still make it, however, and the rest of Agatha's team is not threatening to it; even Golbat's Air Cutter is only a 3HKO, and all the other moves her Pokémon have do no better than that.
Elite Four Lance (Indigo Plateau, Dragon-type): Pinsir can try setting up against Gyarados, but it will likely be in vain. Aerodactyl 2-3HKOs with AncientPower and Wing Attack, as well as outspeeding Pinsir; a Swords Dance guarantees Pinsir the Rock Slide OHKO against Gyarados and Aerodactyl, as well as the Return OHKO (otherwise a 2HKO) against the two Dragonair, but Dragonite remains an obstacle Pinsir finds difficult to surmount, as its Hyper Beam can 2HKO and it also outspeeds. Depending on how the fight is juggled, Pinsir may manage to do some work here, but not a solo.
Champion Rival (Indigo Plateau): Pidgeot still gets 2HKOed by Rock Slide, but due to its FeatherDance, Pinsir has no room to set up against it. Rhydon can make short work of Pinsir with Rock Tomb, avoid that one. The Fire-type, Arcanine or Charizard, will obviously roast Pinsir before it gets to do anything. Alakazam either 2HKOs with Psychic or can put up Reflect to make itself even harder to kill, so fighting it with a much slower Pokémon - as Pinsir is - is ill-advised. Exeggutor or Venusaur are the safest targets, and Pinsir can smash them with Return and some patience; Swords Dance will help with this task. Gyarados and Blastoise have Hydro Pump, but Rock Slide can still 2HKO Gyarados before its Hydro Pump 3HKOs Pinsir; even better if Pinsir is carrying the Swords Dance boost from the fight against the Grass-type, as it will allow the OHKO; Blastoise is much harder to beat, and its Hydro Pump can 2HKO, so Pinsir should either be in high health and at +2 Attack to 2HKO it, or go for the full +6 and OHKO with Return before Blastoise gets to do anything.
Post-Game: This is not anywhere close to where Pinsir should be. Mewtwo will erase it from existence more quickly than it is humanly imaginable.
Pinsir's initial moveset is ViceGrip, Focus Energy, Bind and Seismic Toss. None of them are particularly useful, though thankfully, there are plenty of TMs available for it in the same city. At level 19, it learns Harden, which is more or less redundant. At level 25 it gets Revenge, which would be an okay move to use if it weren't for Brick Break, which comes six levels later and works much better for Pinsir's Speed. Ignore Guillotine at level 37, it will not hit. Submission, at level 43, is in no way better than Brick Break: the recoil and lack of accuracy are not worth the +5 base power boost. Lastly, at level 49, it gets the much better Swords Dance, which its Defense supports quite well.
Pinsir has a wealth of TM options. It can be taught Brick Break and Dig right after capture or purchase, by buying them in the Celadon Dept. Store. Later on, Earthquake can replace Dig for higher power. Bulk Up works as a more defensive option compared to Swords Dance, and offers Pinsir the role of physical tank of the team. While Rock Tomb may sound appealing for coverage purposes, its base power and accuracy actually make it worse than Return, which is a much better general coverage option. If the TM was already spent on another Pokémon, Strength will do just fine.
Alternatively, Pinsir can turn to tutors for even more options. Rock Slide is a move Pinsir can make great use of against some opponents, such as Lance's Dragonite. It can also opt for Body Slam over Strength if it gave up Return. Pinsir can even run Focus Punch in combination with Substitute.
Recommended moveset: Bulk Up / Swords Dance, Brick Break, Earthquake, Rock Slide / Return
Rock-types: Any Rock-type is a good partner for Pinsir, resisting its relevant weaknesses and (with dual types) working well against its own Rock-type cousins. Dual Rock-types are available in several flavours, as well, though they should retain the relevant resistances to work properly.
Water-types: If Rock-types are unavailable, Water-types are also very good at doing their job. While their STAB covers for Fire and Rock alone, their often available Ice Beam does the rest against Pinsir's so hated Flying-types.
Special tanks: While not entirely necessary, specially bulky Pokémon can help Pinsir in a number of matchups. Having special walls in general is helpful for the team in its whole, especially for Set mode players, who will need far more switch-outs.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
What Nature do I want? Adamant. With the wealth of physical options it has, Pinsir will benefit from an Attack boost the most. Jolly and Naughty are second best options, and just about anything that lowers Special Attack is acceptable. Whatever lowers Attack is obviously bad.
How good is Pinsir in a Nuzlocke? As far as Bug-types go, it is as good as it gets. Basically the best one could possibly hope for in Kanto. As a Pokémon in general, it is not exceptional, but it is still quite good. It covers the physical tank niche well and can hit fairly hard, despite the lack of STAB. It struggles in a few matchups, but can manage well on its own against most enemies.