Start with eleven in one e four e six;
onze - eleven in French, and in chess 1. e4 e6 is the French defence.
add what is missing from otherhood, oke, icks;
bronze - br is missing from brotherhood, broke, bricks (credit Omega Krypton).
improving position, go upwards by one;
silver - one position above bronze.
mix up for organs, remove fifty-one.
vers - livers (mix silver) minus li (credit Omega Krypton).
Add to the end an American nation;
versus - appending the United States.
abbreviate all and add short operation;
VSOP - Vs as an abbrev. for versus and add op for operation.
age for a few more years, then turn around;
ox - VSOP brandy is at least 4 yrs old, XO (Extra Old) is more than six years then reverse.
prefix by fifteen – a trap on the ground!
fox as F is fifteen in hexadecimal.