Kome kōji, or "malted rice", is a Japanese ingredient of rice inoculated with koji mold. The koji breaks down the starches and proteins in the rice, releasing glucose and amino acids that become available for fermentation.
Kome kōji is used in the production of seishu, miso, vinegars, pickles, soy sauce, shochu and awamori spirit.
Note that while kome kōji is sometimes called "malted rice" in English, it is not truly malted, as the rice is degerminated before it is inoculated with koji. Kome kōji does play a similar role in fermentation as malted grains do in Western techniques, which accounts for the sense overlap.