The chairback seating in Sections 4 and 5 begins at Row 6. Just below, Rows 1-5 will only have bench style bleacher seating with no back support.

Chairback Seating in Section 6 at DKR Texas Memorial Stadium
Chairback seating begins at Row 6 for Sections 3-6, while rows 1-5 will not have any back support

Photo Credit: jasonfrench via Flickr