English: It was taught, R’ Meir says: “Hear, O Israel, Hashem is our God, Hashem is One” — up to this point requires kavanah of the heart.
On the daf / in context: The essential acceptance of the yoke of Heaven is concentrated in the first verse; therefore special intentional concentration is required precisely there.
Type of Learning
Custom (limitation of the strict kavanah requirement to the opening verse).
What Is Learned
The first verse of the Shema demands focused intention of the heart; that is the core of kabbalas ol malchus shamayim.