I asked…and received this answer …from NGK: …part numbers for BP6ES are 7333 for USA, silver box made in Japan: and 7811 yellow red box-made in France, EU and UK part number. The plugs…NGK says…are the same.
There are similar for BP5ES…two part #s…and for other plugs…do note however…some places automatically substitute the new BPR6ES…resistor plug, with 5,000 ohms per plug, rather than 1,000 ohms. NGK says the BP5ES BP6ES is no longer being made…NOS can be found. All now replaced by the resistor…double check if buying on web. I did…and now have a life time supply.
Nick