English: Rabbi Yehudah says the tzitz provides atonement only while it is on the Kohen Gadol's forehead; Rabbi Shimon says it provides atonement even when it is not on his forehead.
On the daf / in context: See the cited source for the full section.
Type of Learning
Derash on the verse.
What Is Learned
The Gemara debates whether the tzitz's atoning effect depends on its being worn.