Conversation so far:
What was Anton Rubinstein's technique?
Villoing had worked with Rubinstein on hand position and finger dexterity.
What did the critics say about Anton Rubinstein's technique?
Critic Harold C. Schonberg describes Rubinstein's playing as that of extraordinary breadth, virility and vitality, immense sonority and technical grandeur in which all too often technical sloppiness asserted itself.“

Question: Who did he learn his technique from?
Self-contained rewrite: Who did Anton Rubinstein learn his techniques from?