Possible Clues:

• It has notice saying 'For Children Only'!
• Lurch up and down
• Lack stability
• Board to which bishop's responsibility was handed over
• Up-and-down or back-and-forth movement
• View and viewed the ups and downs
• For occupying children it has its ups and downs
• Up-and-down game
• Oscillate up and down
• Visually, one goes up and down