The Very Special Fortune Slip is a series of world quests in Genshin Impact that is tied to the story of the Electro nation Inazuma. It will have you go through special missions as an unofficial member of the Shuumatsuban, a secret ninja organization under the Yashiro Commission.
In this world quest series, you investigate what the Fatui has been plotting to infiltrate the secret organization. This series involves three different world quests: Shuumatsuban Operations, The Replacement’s Secret, and Where the Dandelions Find Rest.
However, this world quest series is straightforward to miss because the prerequisite missions are all hidden. You can only unlock the said mission when you pick up some tattered notes by one of the Shuumatsuban members. These notes can be found in an abandoned camp on a mountain in Araumi.
Following the discovery of the tattered notes, you need to visit the Grand Narukami Shrine to draw a bamboo slip and have it exchanged for a Strange Fortune Slip. This version of the fortune slip has clues and instructions of a special Shuumatsuban mission that you need to complete for that day.
You need to do a mission via the Strange Fortune Slip for five days to trigger the part where the shrine maiden interrogates you and, given the situation, propose that you become an unofficial member of the Shuumatsuban. Please see this guide to know more about the Strange Fortune Slip missions.
After completing all five secret missions, revisit Inazuma City, and you will get a cut scene that indicates a new mission is available. In the said cut scene, someone bumped into you and secretly slipped a piece of paper into your hand, which shows two drawings.
The drawings are a cage or cell and a shuriken, meaning you have to visit and check with the real Gendou Ringo for any updates on the missions with the Shuumatsuban.
This triggers the first world quest of the series.