101Leafy researched the game with the Hilltop Works fan translation patch, English translation by Cargodin
Chungking Key重慶花園の鍵
Chungking Key is item 86 of the game's item table, in the Items group. The script never names it.
Grants access to Chungking Garden
重慶花園はえび剥き屋の脇から入る。
It never shows up on its own in a talk with a picture, so it has none here.
Item table: Monster ROM Chungking Key Mainspring
English translations by Cargodin for Hilltop Works Fan Translation Patch: https://www.patreon.com/hilltopworks/posts/kowloons-gate-160555525?collection=18503