WDB ACFT HAS CLRNC CHANGE BUT DOES NOT REALIZE IT. NAV ERROR.

Narrative

JUST PRIOR TO PUSHING BACK FROM OUR NARITA; JAPAN JETWAY; WE RECEIVED A CLRNC WHICH; AS IT TURNED OUT; DIFFERED FROM OUR FILED FLT PLAN--(FILED AND INS LOADED: CHOSHI FOUR DEP; OTR 11 KAGIS; PABBA; ADNIP; R591 ADGOR; ETC. CLRED: 'CHOSHI FOUR DEP; OTR 11 KAGIS; ABETS; R591; FLT PLAN RTE'). R591 IS A RTE MADE UP OF WAYPOINTS BEGINNING WITH THE LETTER 'A.' WHEN I COPIED THIS CLRNC SIMULTANEOUSLY WITH THE COPLT; I HEARD A WORD FROM THE JAPANESE CTLR'S VOICE WHICH BEGAN WITH THE LETTER 'A' AND ASSUMED THAT WORD TO BE THE FIRST FILED 'A'--WORD ON R591. NOTHING WAS STATED BY THE CTLR AT CLRNC DELIVERY ADVISING OF A CHANGE FROM FILED FLT PLAN. AS PROC DICTATES; IMMEDIATELY UPON RECEIVING ATC CLRNC; WE COMPLETED PREPARATIONS FOR PUSHBACK. NO MENTION OF A CLRNC CHANGE WAS MADE BY ANY OF THE 4 PLTS IN THE COCKPIT. ON CLBOUT A FEW MI PRIOR TO KAGIS; I CHKED THE COORDINATES OF THE NEXT WAYPOINT IN THE INS (PABBA); ENGAGED THE AUTOPLT TO TRACK THE INS AND TURNED THE ACFT CTL AND COM OVER TO THE COPLT. THIS ACTION ALLOWED ME UNINTERRUPTED TIME TO PERFORM MY PAX PA DUTIES; UPON COMPLETING THE PA; I 'REJOINED THE LOOP' TO BE TOLD THAT WE HAD BEEN CLRED DIRECT TO 'ADGOR; FLT PLAN RTE FROM A POINT APPROX 20 MI NE OF KAGIS. ADDITIONALLY; I WAS INFORMED WE WERE POSSIBLY OFF COURSE AS OUR CLRNC WAS TO PROCEED E OF KAGIS TO ABETS; THEN R591 AND THAT THE JAPANESE RADAR CTLR; ALTHOUGH NOT MENTIONING OUR COURSE DEV; MAY HAVE BEEN KINDLY ALLOWING US TO CONTINUE ON OUR NE COURSE AS IF NO ERROR HAD OCCURRED. SUBSEQUENT DISCUSSION INDICATED THAT OTHERS HAD HEARD THE CLRNC DELIVERY CHANGE TO OUR FILED RTE BUT HAD HAD THEIR ATTNS DIVERTED BY THE IMMEDIACY OF THE PUSH-BACK REQUIREMENTS. LESSONS LEARNED: I SHALL COMPARE EACH WORD OF THE CLRNC WITH FILED FLT PLAN. IF I HAVE DIFFICULTY UNDERSTANDING A CTLR; I SHALL ASK FOR A REREADING. IF ANY DOUBT ARISES; I SHALL STOP THE PROCS TO CHK WITH OTHER CREW MEMBERS AND CHARTS. I SHALL ASSUME NOTHING.