Linji Yixuan's death in 866 is well documented in Chan biographical tradition, including the Linji lu compiled after his death, but the same tradition gives no birth year, and standard reference works represent his life as a bare range with the birth end left open.
What would resolve this A dated biographical notice from Linji Yixuan's own lifetime or from Huangbo Xiyun's circle fixing his age or birth year, distinct from the undated account of his training and later teaching career.
OpenTang dynasty Chan Buddhist historyRobert E. Buswell Jr. and Donald S. Lopez Jr., The Princeton Dictionary of Buddhism