Kriegspiel is a relatively old variant, the inventor was Michael Henry
Temple (1862-1928).
One of the few top-level chess masters to have taken up Kriegspiel before
this days was Alekhine, as is shown by quotes from the 1926 BCM (March,
page 124 and July, page 314 respectively):
‘Monsieur Alekhine (now a naturalized Frenchman and an official
representative of French chess) remained in this country for a short time
after his success at Hastings. On 9 January he spent the afternoon at the
Imperial Chess Club playing Kriegspiel and beat every one of his
opponents. Kriegspiel is a lighter branch of Chess.’