Question: Which people had the best 10-year period when Fischer had best 15-year period?
SQL: SELECT "best 10-year period" FROM "1-1710426-2" WHERE "best 15-year period" = 'Fischer';

Question: Which people had the best 10-year period when Capablanca had the best 15-year period?
SQL: SELECT "best 10-year period" FROM "1-1710426-2" WHERE "best 15-year period" = 'Capablanca';