Yakuza 4 Remastered

Memos are things you can find in the game that’ll tell you more about game mechanics whether it be about 1 of the 4 characters fighting styles or something about the city. You’ll find a majority of these during your regular playthrough simply by doing the action or by talking to people around the city that have a blue arrow over their heads. After you've gotten your last memo check the memo list cause the achievement may not unlock automatically when you get your last memo. This list comes from CyricZ from gamefaq which has made amazing guides for all the Yakuza games. Here’s a link to their guide of this achievement https://gamefaqs.gamespot.com/ps4/239456-yakuza-4-remastered...

Part 1 Memos:
Action Icon - At the very beginning of the game, speak to the man in the business suit to the east of the Matsuya at the end of Tenkaichi St.
Special Editions of Magazines - In the first chapter, you'll find a chubby guy with a backpack in Theater Square.
Using Items - The northeast part of Theater Square, near the entrance to the Theater Underground, the guy with glasses.
Equipment 1 - Shichifuku St. near the northeast part of Theater Square, a guy with glasses and a ponytail.
MEB - Inside the Men's Entertainment Box, speak to the dude in the camo jacket.
Pros and Cons of Getting Drunk - A woman seated at the bar inside Bantam.
Finished and Complete - Guy in a blue jacket in front of Millennium Tower.
Using the LS and RS Buttons - A flashy barker just outside of Le Marche.
Experience Points and Leveling Up - There's a lady on the eastern rooftops, right next to the Pink Alley stairs.
Equipment 2 - Just north of Club Shine on Pink St., speak to the guy in the red jacket.
The Underground - The old man in a brown jacket east of the Tenkaichi gate.
Emails - A girl in a blue jacket at the southeast corner of Theater Square. (Chapter 2)
Rooftops - An older guy in a gray suit southwest of the Matsuya on Tenkaichi. (Chapter 2)
Coin Lockers 1 - A guy in a suit standing near the lockers on Taihei Blvd. (Chapter 2)
Non-Japanese Speakers - A kid with a messenger bag in Tenkaichi Alley, near Publick Park 3 (Chapter 2)
Naomi's Palace - The woman just outside Naomi's Palace (Chapter 2)
Getting Help Around Town - Speak to the man in the suit inside Kyushu No. 1 Star (Chapter 2)
Recovering Health - Just outside of Earth Angel in the Champion District is a young woman (Chapter 2)
Valuables - A kid in glasses standing west of the Park Boulevard taxi stand. (Chapter 2)
Akiyama: Allies - Speak to the homeless man standing west of the Park Boulevard taxi stand. (Chapter 2)
Taxis - Speak to the man near the Taxi Stand at the Hotel District (north end) (Chapter 2)
Substories - Enter Shellac and speak to Aoki, the guy sitting at the bar. (Chapter 2)
Coin Lockers 2 - A lady in a knit hat will be standing next to the Underground lockers. (Chapter 3)
Maps - On the Western rooftops, there is a guy on a spot on the roofs north of Suppon and south of Taihei. He's in the southeast corner of the block, down some stairs at a dead end. (Chapter 3)
IF7 - Speak to Sukegawa right next to Minamida's machine.

Part 2 Memos:
Police Patrols - In Chapter 3, speak to the guy at the south end of Nakamichi St. He should be right in front of Saejima as you enter Kamurocho.
Kicking Objects - In Chapter 3, speak to a guy in front of Smile Burger.
Manholes - In Chapter 3, speak to the old man in front of Children's Park.
Soul Orbs - In Chapter 3, speak to the homeless guy in the Millennium Tower Basement.
Another Perspective - In Chapter 3, once you enter the north sewer (not the central sewer), speak to the homeless man in the red jacket on the path.

Part 3 Memos:
Little Asia's Adopted Son - This dude is hanging outside Shichifuku Parking Lot. You'll practically trip over him as you go here for the story.
Avoiding Fights - Once you meet Akaishi, speak to him in Theater Square.

Finale Memos:
Switching Main Characters - Speak to Date in New Serena.
Main Characters' Possessions - Speak to Akiyama in New Serena.

Full List of Memos:
System
Memos
Save Points
Action Icon
Recovering Health
Switching Main Characters
Main Characters' Possessions
Left stick and Right stick

Pause Menu:
Maps
Emails
Using Items
Equipment (1/2)
Equipment (2/2)
Valuables

Combat:
Akiyama's Fighting Style
Saejima's Fighting Style
Tanimura's Fighting Style
Kiryu's Fighting Style
Heat Actions
Kicking Objects
Destructible Objects

Chase Battles
Chase Battles (Fleeing)
Chase Battles (Pursuing)
Other Chase Battle Techniques

Leveling Up:
Experience Points and Leveling Up
Soul Orbs
Revelations
Daijiro Saigo's Training - Akiyama
Master's Helper - Saejima
Supporting Detective Nair - Tanimura
Developing Heat Actions

Adventure:
First-Person Mode
Akiyama's Allies
Manholes
Lockers (1/2)
Lockers (2/2)
Substories
Finished and Complete
Pros and Cons of Getting Drunk
Special Editions of Magazines

Kamurocho:
Rooftops
Underground
Kamiyama Works
Non-Japanese Speakers
Little Asia's Adopted Son - Tanimura
Taxis
Naomi's Palace
MEB
The Coliseum
Fighter Maker
IF7-R

Street Fights:
Avoiding Fights
Getting Help from People - Akiyama
Police Patrols - Saejima
Police Scanner - Tanimura
Gang Encounters - Kiryu