The BA move is intended as a temporary response to fill empty seats, but the vast amount of capacity between the UK and Japan is likely to keep fares low. Between them, BA, All Nippon Airways, Japan Airlines and Virgin Atlantic offer 36 wide-bodied flights each week from Heathrow to Tokyo and back; 16 Boeing 747s between Heathrow and Osaka; and a further five non-stops to and from Nagoya. In addition, dozens of airlines, from Aeroflot to Thai, offer one-stop connections between Britain and Japan. On such a long haul, the "express" route across Siberia plied by the non- stop airlines is the ideal way to travel, but the connecting possibilities help to keep fares down.
For a couple of decades, the number of Japanese visitors to Britain has eclipsed the tourist traffic in the opposite direction. Now, though, the tide has begun to turn. One reason is the economic downturn in Japan; another is a quirk in international aviation. For the past three years, All Nippon and JAL have been offering excellent fares between Britain and Australasia. Besides being the most direct route from London to Sydney, the arrangement allows an optional stopover in Japan. So thousands of travellers have enjoyed a glimpse of one of the most intriguing nations on earth.
And once you have visited Japan, it is difficult to resist the chance to return. For world-weary travellers, Japan provides blessed relief: a scru- pulously clean, safe, efficient destination which is endowed with all manner of attractions. Furthermore, it offers one of the best travel deals anywhere in the world: the Japan Rail Pass. One week's access to the network of shinkansen (bullet) trains and a dense web of local services costs just pounds 130, and will whisk you across most of the length and breadth of the archipelago. High velocity means you can maximise your visit with minimum effort. From Sapporo on the northern island of Hokkaido to Nagasaki on Kyushu, the south-western island, I have watched town and country whizz past at speeds approaching 200mph.
The first-time visitor, though, should concentrate on the great cities. Tokyo is a mesmerising agglomeration of dozens of distinct districts in which to immerse yourself. Two personal highlights, reflecting commerce ancient and modern: the fish market at dawn, when an electrifyingly theatrical chorus of auctions takes place; and the futuristic Sony centre, where the technology that will take us through the 21st century is shown in an anonymous 1960s office block.
The other safe bet for a short break is the Kansai region, encompassing Kyoto, Osaka and Kobe, plus much more. If you base yourself among the shimmeringly serene temples of Kyoto, the railways will take you easily to the rest of the region. For me, the most heroic sight is the way that Kobe is growing after the devastating earthquake - not so much rebuilt as re-invented in an even more majestic manner. Glinting offshore, on reclaimed land in Osaka Bay, is the elegantKansai International Airport.
Man does not have the upper hand in all of Japan, but the mountainous terrain that makes up much of the country is relatively accessible - up to and including magnificent Mount Fuji, the perfect volcanic cone so important to the Japanese soul.
Yes, but what about the cost? When I visited the almost-tropical island of Okinawa in 1995, sterling was miserably low against the yen - much closer to 100 than the present rate of around 200. Yet, even then, it was entirely possible to find good, cheap accommodation in a traditional ryokan - all paper walls and tatami mats, with an invariably hospitable proprietor. Japan has always represented excellent value; it is now looking positively inexpensive.
The substantial swing in exchange rates means it is now Japanese visitors to Britain who are having to economise. Fortunately, the established infrastructure for incoming tours is adept at providing good value. The best way to maximise spending money is to explore Britain beyond the usual tourism circuit of London, Bath, Stratford, York and Edinburgh - all fine places, but the demand for accommodation in summer can force prices up. For a clearer view of Britain, once again the train is the best way to travel. Competition on the newly privatised railways means there are some excellent bargains. On the closest Britain has to a bullet train, the 400-mile East Coast line from Edinburgh to London, you can travel anywhere for just pounds 12, so long as you begin after 8pm.
If I were to design a two-week itinerary for a Japanese visitor, it would inevitably begin and end in London. The tourist who takes a more rounded view of the capital than just the central core will be enriched by the distinctiveness of Brixton and Camden, Chiswick and Docklands.
Next, use Bath as a springboard for south-west England or Wales, whose landscapes get more dramatic the deeper you go. Stratford is a mandatory stop, but few visitors couple the Shakespeare trail with a visit to the town's fine racecourse; there are few more pleasurable activities than losing a few modest wagers on a summer's evening just outside Stratford. Across in East Anglia, Norwich remains one of Britain's finest cities, and is comfortably off the main tourist trail.
Going north, Birmingham, Leeds and Manchester demand attention, as does the singular city of Liverpool. And as next year's City of Architecture and Design, Glasgow is challenging the cultural credentials of Edinburgh more strongly than ever.
The tallest mountain in Scotland, Ben Nevis, struggles to top 4,000ft; puny by Japanese standards, but in the hauntingly beautiful context of the Highlands it is the perfect scale. New ferry links mean that from Scotland you can easily reach the corner of the United Kingdom most neglected by the English, Welsh and Scots: Northern Ireland, where much of the natural beauty remains unscarred by progress or strife.
Simon Calder is Travel Editor of The Independent
Key contacts for people travelling from Britain to Japan
All Nippon Airways: 0171-355 1155
British Airways: 0345 222111
Japan Airlines: 0345 747700
Virgin Atlantic: 01293 747747
Specialist tour operators selling the Japan Rail Pass
Jaltours: 0171-495 1775
Nippon Travel: 0171-437 2424
Japan Travel Centre: 0171-287 1388
Japanese Embassy, 101-104 Piccadilly, London W1V 9FN (0171-465 6500).
Japan National Tourism Organisation, 5th Floor, Heathcoat House, 20 Savile Row, London W1X 1AE (0171-734 9638).
Japanese Chamber of Commerce, 2nd Floor, Salisbury House, 29 Finsbury Circus, London EC2M 5QQ (0171-628 0069).
To call numbers in Japan from the UK, dial 00 81 followed by the subscriber's number without the initial zero.
Key contacts for people travelling from Japan to Britain
All Nippon Airways: 03 5489 1212
British Airways: 03 3593 8811
Japan Airlines: 03 5460 0511
Virgin Atlantic: 03 3499 8811
British Embassy, 1 Ichiban-cho, Chiyoda-ku, Tokyo 102 (03 5211 1100)
British Tourist Authority, Akasaka Twin Tower 1F, 2-17-22 Akasaka, Minato-ku, Tokyo 107 (03 5562 2543)
To call numbers in the UK from most telephones in Japan, dial 001 44 followed by the subscriber's number without the initial zero.