We are pleased to announce the first half of the SSBD 2021 update, which includes 1799 image datasets (8TB) and four quantitative datasets (6MB). We have a plan for the second half of the 2021 update until next spring. Added datasets are 70-Yoshida-KTMTDyn, 72-Kyogoku-CytoplasmNucDyn, 120-Ding-CentromericDyn, 126-Imanishi-CellMorNuCyM, 127-Konishi-ERKDyn, 128-Muta-IECsERKDync, 129-Komatsu-ERKBiosensorActivity, 130-Sano-CellMigrationDyn, 161-Tanaka-MEFMitochondrial, 165-Kinjo-ERKactivity, 166-Takubo-ECsTrajectory, 171-Ochi-Hes1DynNPCs.