The locker keys are not very hard to find in Yakuza 4. They are glowing – mostly where there is no light/night. There are a total of 100 locker keys in the game and all of them are mostly at common places.
The locker keys are used to unlock the bus lockers, these bus lockers have various items which you can collect such as weapons, armor, items etc. You can find these keys on the streets and inside the buildings (shops, rooms etc).
Taihei Street Lockers Keys
Tattered Scarf Chapter: 1-2
At the front of “Cafe Alps” which is situated at the place where Nakamichi St. and Nakamichi Alley intersect with each other.
Steel Mail Chapter: 1-2
Accept the “See the babes” offer which is given to you by a guy at the Pink Street. He will now allow you to Asia. The key is lying on the lobby’s floor.
Demon Stone Chapter: 1-2
At the corner of the beam you’ll find a plant along with the key.
Spicy Knife Chapter: 1-2
Find a file cabinet at Kamuro Theater. It is at the top of it.
Eye of the Dragon Chapter: 1-2
Showa Street, the 2nd store of Poppa convenience.
Hyper Stun Gun Chapter: 1-2
Taihei Blvd, go over the tunnel which has the locker bank and look for a sign, then zoom on the left side of it.
Shape Memory Spring Chapter: 1-2
It is in the far corner of the alley (champion district).
Pearl Chapter: 1-2
It is in the Ebisu pawn shop at the left side to the entrance.
Mystery Stone Chapter: 1-2
At the ventilation tube which is next to Kamiyama Weapon shop.
In the alleyway behind Kotobuki Drugs, on a pipe above a couple of blue trash cans.
Ancient Steel Chapter: 1-2
Look outside the Kanrai (Shichifuku St. East)
Broken Radio Chapter: 1-2
It is near the black wall (M Store).
Blackjack Amulet Chapter: 1-2
The blackJack is on the table (Bantam’s Back Wall).
Tauriner Maximum Chapter: 1-2
Go towards the western side from the Taxi Stop of the Northern Side (Park Blvd).
Zero Jewel Chapter: 1-2
Near the counter (Kotobuki Drugs).
1-1-1 Card Chapter: 1-2
At theater square look for a blue vending machine, the card is on its top. It is in the Shichifuku Street.
Toughness Emperor Chapter: 3-1
In one of the bathrooms in the alley which comes from the homelands front door.
Silver Plate Locker Keys
Physimagic Jersey Chapter: 1-2
At the Showa Street you’ll find some parked bikes. The jersey is in the basket of one of the bikes.
Charisma Ring Chapter: 1-2
Go to the eastern side of the Parking lot. It is at an empty space (Taihei Blvd-Eastern Side)
Piss Mountain Stone Chapter: 1-2
The stone is placed at one of trees near the entrance of Millennium Towers.
Goddess of Children Amulet Chapter: 1-2
If you don’t find this during Akiyama’s part of the game, you may actually need to talk to a doctor about your eye-sight. In the middle of Tenkaichi Street – right outside New Serena.
Small Motor Chapter: 4-2
At the corner of New Serena, on top of a light fixture.
Gravity Converter Chapter: 1-2
Look through the pile of collapsed cardboard boxes of the Western Entrance (Showa Street). The Locker Key Radar must be equipped.
Antique Chain Mail Chapter: 1-2
There is a dead tree in the children park. That’s where you need to look.
Staminan Spark Chapter: 1-2
At New Serena Block, the stamina spark is at the top of the building left to the vending machines. You will have to zoom-in.
Pearl Chapter: 1-2
In the Orchid Palace, near aisle – between the tables.
Comfy Shoes Chapter: 1-2
The key is right in front of the back door of the Kyosho.1…near the clerks counter.
Mystery Liquid Chapter: 1-2
At Millennium Tower North in a tree.
Royal Joker Card Chapter: 1-2
It is in the Nakamichi Street Club SEGA.
Even Goro’s Beads Chapter: 1-2
This is the street where you rescue “Zhao”. The beads are on the second floor of the near-by buildings.(Senryo Evenue)