The Stardew Valley 1.3 update is probably best known for adding multiplayer features to the game, but that was only one of many features added. New items such as the garden pot and auto-grabber were added, as well as the new Night Market event. The purpose of this Stardew Valley guide, however, is to go over the secret notes that were added, specifically the 20th.
How to Get the Magnifying Glass
Before players can even start looking for secret notes, they must activate a certain scene. Most players will probably activate it without intending do, but it has to be activated in Stardew Valley's winter, which may serve as a bit of a roadblock if players are in earlier seasons. If it is winter though, then to activate the event, just walk from the farm to the bus stop between 6am and 4pm and the event will trigger.
Players will see a shadow being who is likely Krobus, who will then run off. He needs to be followed all the way to the playground in town next to the community center. Interacting with the bush in the area will cause the shadow to pop out and give the player the magnifying glass item. Once the player has that, the player will be able to find secret notes.
How to Find Secret Notes
There are 25 secret notes for players to find as Stardew Valley's 1.5 update. They can be found randomly in a number of ways: cutting weeds, defeating monsters, fishing, digging up artifacts spots (the worms on the ground), chopping lumber, breaking stone, breaking meteorites, or from giant crops.
Some methods have a higher chance of dropping notes than others with defeating monsters, breaking meteorites, large stumps, logs and boulders, and harvesting giant crops producing the highest chance. Fishing and artifact spots have a bit of a nebulous drop rate of secret notes, as they will only attempt to spawn a secret note when trash would have been fished up and when an artifact spot wouldn't have produced an artifact or winter forage. A giant crop however, will always result in the game attempting to spawn a secret note.
However, due to the way the game attempts to spawn secret notes, players may not always get a note when the game attempts to spawn one. When the game attempts to spawn a note, it will generate a number between 1 and 25 three times. If the player doesn't have the number associated with the first number generated, they will receive that note. If they do have that note, the game will generate the second number and repeat the process. If the player has notes for all three of the numbers the game generates, then a note will not spawn.
How to Solve Secret Note #20
Once a secret note is obtained, it will move to the player's menu where all obtained notes can be read. As for Secret Note #20, it shows a circle and a bunch of directional arrows underneath the circle. Start in the center of the town square and move in the directions indicated until an obstacle is hit, and then move in the next direction until an obstacle is hit, and so on.
If done correctly, players should arrive at the truck by the JojaMart (or movie theater if that's what players have instead). Speak to the driver of the truck who will request a rabbit's foot, an item occasionally dropped by rabbits in the player's Stardew Valley coop. Give the driver the rabbit's foot and they will give the Special Charm in return.
The special charm is a permanent item that will increase the player's daily luck. Higher luck is useful for activities such as mining and resource gathering.
Stardew Valley is available now on Mobile, PC, PS4, Switch, and Xbox One.
Source: Stardew Valley Wiki