9. Rule of sixteen

1NT by North, passed out. Which major should I lead? I led a small heart. Silly me, I had forgotten the weird 'Rule of Sixteen'. Against a freely bid no-trump contract, with four two-card suits to an honour, you add the pips together and lead the suit which is NEAREST to sixteen. In this instance, spades add up to 15, hearts to 18, so spades it must be. Spades kept declarer to nine tricks, whereas he can develop ten tricks on a heart lead.