CREATE TABLE table_56588 ("Outcome" CLOB, "Date" CLOB, "Surface" CLOB, "Opponent" CLOB, "Score" CLOB)

What suface during the game that had Yevgeny Kafelnikov as an opponent?
SELECT "Surface" FROM table_56588 WHERE "Opponent" = 'yevgeny kafelnikov'
SELECT "Surface" FROM "table_56588" WHERE "Opponent" = 'yevgeny kafelnikov'