This research studies the numerical expression of the color perception corresponding to twelve opponent word pairs through two-point and seven-point assessments carried out by Thai observers. The twelve color perception equations were derived from the relationship between the colorimetric values and visual assessments. The obtained visual results between methods and countries (Thailand-Japan) were compared by determining correlation coefficients and paired t-test in terms of hue and tone at a significant level of 0.05. Relationships of twelve word pairs between methods were high with the range of correlation coefficient value 0.9718-0.9885 while hue differences were found in "Warm-Cool" and in "Gaudy-Plain" of achromatic color and tone comparisons were different at all twelve tones. There was a significant relationship between countries, with the exception of the "Deep-Pale." Hue differences were found in "Warm-Cool," "Deep-Pale," and "striking-Subdued." Tone differences tended to occur in all twelve tones. Note that cross-cultural translation equation between Japanese-Thai data is possible, by which a color perception map was established. This map is useful to directly translate the magnitude of the color perceptions of Thai and Japanese.