YOHKOH Observations Related to Coronal Heating (Invited)

Yohkoh observations of microflares (transient brightenings) and nanoflares are presented. The frequency distribution of transient brightenings is found to be a power law with an index of 1.5 - 1.6 in the energy range greater than 10²⁷erg. Short time-scale variability fainter than transient brightenings is found in the soft X-ray position-dependent light curves. Time variability is found almost everywhere in active regions and X-ray bright points, while no significant variability is found in the quiet Sun.