Over the last few weeks I've been bulking up my collection of Megadrive shooters, with many of the games being Japanese or American versions since a number of them were never released in Europe. So with that in mind I thought it was about time I did another of my guides to import gaming, focussing on Sega's most successful console...
Why Bother Importing?
The Megadrive was incredibly popular in Europe, much more so than in Japan (where Nintendo has always been king) and equally as popular as in the USA, yet strangely it still has a much smaller library of games than those two regions. Additionally there were a number of games released in Europe that were heavily censored or modified compared to the Japanese originals, such as Konami's Castlevania and Contra games. Add to that the sheer number of games available at low prices from the US and you have three good reasons to import for the console!
If you want another, purely cosmetic reason to import, then the box art on most Japanese games is absolutely gorgeous in comparison to the western equivalent.
Hardware Modification
There are probably more ways to import-enable the Megadrive than any other system, and the first of these is about as cheap and easy as it gets - do nothing! The vast majority of Megadrive and Genesis game cartridges do not actually have any region protection in them. The common consensus is that every game released prior to Sonic the Hedgehog 2 in 1992 has no regional lockout, while only selected games that came out after that time have it. There is however a physical restriction with Japanese games as the cartridge won't fit into the standard slot of a western system, but this can be easily worked around by cutting a small piece of the console shell away either side of the cartridge slot.
The next cheapest option would be to pick up an import game converter cartridge, of which there are many, which will generally set you back no more than £10. The most well known of these is probably the Game Genie, which was marketed as a cheat cartridge in the US. The cartridge works as a pass-through which not only disables regional lockout on some cartridges but also allows you to get around widening the cartridge slot for using Japanese games. Be wary however as I believe that some of the games released later in the Megadrive's life employ more complex regional lockout that some cartridges cannot circumvent.
A third option would be to pick up a cheap Japanese Megadrive. You really only need to get the base unit itself as the PSU, AV and controllers from all systems are compatible with each other as far as I'm aware, as long as it is the same model. This would give you full compatibility with all Japanese releases of course, and also allow you to use most European and American cartridges (which physically fit) providing they had no lockout.
Finally the most comprehensive way to make your system compatible with imports from all regions is full modification - widening the cartridge slot and fitting switches to allow you to select the system's language (English or Japanese) and also the display output frequency (50 or 60Hz). The two switch mods are particularly useful because it is one (or both) of these two settings that the regional lockout in game cartridges uses to verify the region of the console, so if you are able to modify each of these to emulate a system from any region, there is no game that you won?t be able to play!
If you're brave enough to try modifying the system yourself then detailed instructions can be found at Mmmonkey's Console Modifications, but if you'd rather leave it to an experienced professional then Console Passion offer full modification for £25 plus postage costs, or will sell you a modded Megadrive base unit for the same price.
Where To Buy Cheap Games
As you'd expect, many of the really desirable import-only Megadrive games tend to demand a premium, but there are still quite a few bargains to be had if you shop around, and you should be able to pick up some loose cartridges for under a fiver with many boxed games costing less than £10. As the Megadrive was a very popular console for imports during its original lifespan, you'll find quite a few Japanese and US games readily available on Ebay UK and the independent retro game stores like Console Mad, Genki Videogames and Console Passion, though the latter two tend to be fairly pricey. If you're looking to genuinely import your games then both Hit Japan and Superb Articles From Japan have a decent selection of Japanese titles, while Lukie Games is a good option for Genesis titles, though most are lacking boxes or instructions. As always, buying bulk lots from one seller can offer you significant savings on games from overseas, as can making 'Best Offers' if possible.
Since I last wrote one of these Import Gaming articles I have found another method for getting hold of some decent stuff from Japan at competitive prices. Shopping Mall Japan offers a service where they will buy items on your behalf from Yahoo Japan Auctions (which is generally inhospitable towards western users) and store them locally until you are ready to have them sent over in a bulk parcel.
Setting up an account with them is a little convoluted and it is very important you read and understand their policies regarding fees and shipping options, but there's no doubt that you can get some bargains if you focus on Yahoo auctions that feature bulk lots of games. For example, I bought a bundle of 22 Megadrive games sold in one lot and even after paying all the fees, local and international shipping they still only cost an average of under £4 each! 
Finally it is always worth checking out gaming forums such as the one at Sega-16 as some bargains may appear on their sale boards.
What Games To Buy
As I mentioned at the start of the article, I've been importing quite a few Megadrive/Genesis shmups recently, but overall I've built up a fairly balanced selection of games from both the USA and Japan. All of the following were bought for £10 or less and are boxed, though some are missing manuals. A few of them were released in Europe but those versions will cost you a hell of a lot more than their foreign counterparts...
Top Genesis Bargains
Thunder Force III - Technosoft's superlative horizontal shooter, which never got a European release
McDonald's Treasure Land Adventure - fantastic-looking platformer developed by the legendary Treasure
Crossfire - a mixture of scrolling shooter and run n' gun action, known as Super Airwolf in Japan
OutRunners - a very competent conversion of the simultaneous 2-player sequel to Sega's racing game
Top Japanese Bargains
Assault Suit Leynos - Mech-based run and gun action, known as Target Earth in the USA
Puyo Puyo - the eastern version of Dr Robotnik's Mean Bean Machine offers addictive puzzling action
Saint Sword - Taito's hack and slash platformer with a twist
Gaiares - a highly regarded horizontal shooter that allows you to poach weapons from destroyed enemies
Doraemon vs. The Dream Thief and the Seven Gozansu - a Mario-esque platformer featuring the popular Anime character
Remember this is just the tip of the iceberg, and if you pay more than £10 each for any of these then you've not been shopping around enough! If you're unsure what Megadrive gaming delights are out there that you have yet to experience, you should head over to Sega-16 or Segagaga Domain and browse their reviews.
Good luck, and please share your own Megadrive/Genesis import experiences by leaving a comment! 