NO- and N-2-formation behavior during the high-temperature 02 gasification of coal char was examined using a pulse gasification reactor, which minimizes the exothermic heat generation and the secondary reaction of NO. Coal char heat treated at 1300 degreesC was gasified with 10% O-2 in a temperature range from 1000 to 1300 degreesC. Although the total nitrogen converted to NO and N-2 are independent of gasification temperature, a fraction of NO tends to increase with increasing char conversion and decrease with increasing gasification temperature. These trends can be explained by the secondary N-2-formation reaction from NO and char via nitrogen-containing surface species as an intermediate. This result is similar to that observed in the previous study at low temperatures, except that the surface nitrogen species is less stable at high temperature. In another series of experiments, the char prepared at 950 degreesC was subjected to gasification without pretreatment at 1300 degreesC. The NO- and N-2-formation behavior heavily depends on whether the char was pretreated at 1300 degreesC. The release of unstable char nitrogen as N-2 was observed in addition to the N-2 formation from the char-NO reaction when the char was not heat-treated at a severe condition. The relative importance of these two N-2-formation routes determines the final gas composition.