  We report a coordinated multi-band photometry of the RS Oph 2006 outburst and
highlight the emission line free y-band photometry that shows a mid-plateau
phase at y ~ 10.2 mag from day 40 to day 75 after the discovery followed by a
sharp drop of the final decline. Such mid-plateau phases are observed in other
two recurrent novae, U Sco and CI Aql, and are interpreted as a bright disk
irradiated by the white dwarf. We have calculated theoretical light curves
based on the optically thick wind theory and have reproduced the observed light
curves including the mid-plateau phase and the final sharp decline. This final
decline is identified with the end of steady hydrogen shell-burning, which
turned out the day ~80. This turnoff date is consistent with the end of a
supersoft X-ray phase observed with Swift. Our model suggests a white dwarf
mass of 1.35 \pm 0.01 M_\sun, which indicates that RS Oph is a progenitor of
Type Ia supernovae. We strongly recommend the y-filter observation of novae to
detect both the presence of a disk and the hydrogen burning turn-off.
