Thehighrepetitionrate10J/10nsYb:YAGlasersystemanditskeytechniquesarereported.Theamplifiersinthissystemhaveamulti-passV-shapestructureandtheheatintheamplifiersisremovedbymeansoflaminarwaterflow.Inthemainamplifier,thelaserisfour-pass,andanapproximately8.5J/1Hz/10nsoutputisachievedintheprimarytest.Thefar-fieldoftheoutputbeamisapproximately10timesthediffractionlimit.Becauseofthehigherlevelsofamplifiedspontaneousemission(ASE)inthemainamplifier,theoutputenergyislowerthanexpected.Attheendwediscusssomemeasuresthatcanimprovethepropertiesofthelasersystem.