We propose to observe the blank Galactic plane field at (l,b)=(28.6,0.0) for 200 ksec to study energy spectra of Galactic Ridge X-ray Emission. This is a Chandra deep field where we have spent 100 ksec. We will carry out plasma diagnostics of the Galactic ridge emission using primarily iron lines, and also Kalpha and Kbeta lines of Ne, Mg, Si, and S. The 200 ksec Ridge observation by Suzaku enables us to compare Galactic center and ridge emission lines directly. We believe the Galactic Ridge X-ray emission is truely diffuse, based on our Chandra study. However, there is a claim that the ridge emission is preimaly composed of dim sources down to 10^-16 cgs in 2-10 keV. To end the controversy, we plan to carry out a 1Msec Chandra observation on this Chandra-Suzaku field.