claim: Ding Yanyuhang was born in May of 1993.
evidence: X21 may refer to  :. Northrop X-21 , experimental aircraft designed to test wings with laminar flow control. Northrop X-21. Northrop X-21. SA-X-21 or S-400 -LRB- missile -RRB- , anti-aircraft weapon system developed by Russia 's Almaz Central Design Bureau as an upgrade of the S-300 family. SA-X-21. SA-X-21. X. 21 -LRB- sometimes referred to as X21 -RRB- , an interface specification for differential communications introduced in the mid-1970s by the ITU-T. X21 -LRB- band -RRB- , a Japanese girl idol group. de  : X. 21. fr  : X21. fr  : X. 21. it  : X21. it  : X. 21