It's a sad reality that most specialist Japanese gaming shops will only ship to Japanese addresses. At the same time, there are often exclusive bonus items you can only guarantee you'll be able to buy if you preorder directly from a specific store.
There are two different ways that people outside Japan can get around this problem and purchase rare items without having to watch auction sites for months.
Note: These methods aren't free to use and you'll have to pay shipping twice (the items are shipped from the shop to your buying service, then shipped internationally to your home country). Read each site's terms and conditions carefully and ask them for a cost estimate if you're not sure how much you will have to pay.
I'll list the services I have personally used before in each section. Some sites only ship to certain countries due to bad experiences with customers in the past, so please read each company's website carefully for their terms and conditions before making any purchases!
Method 1: Proxy buying services
Proxy services are ideal for people who don't speak Japanese, or for those who want to order from a website which doesn't accept non-Japanese credit cards. You will always pay slightly more with a proxy service, but you have the benefit of knowing they can help with any problems and contact the seller in Japanese for you. Here's a list of the ones I know.
Shopping Mall Japan
This site specialises in auctions but you can also use it to order from online shops. They'll even send an employee out to buy things from a physical shop in Akihabara if you want something rare. Their website is strange and the rules are quite strict, however, I've always found their service flawless and their staff are very polite. They offer a wide range of international shipping options and can accommodate all kinds of weird special requests. One interesting feature they offer is shopping in Taiwan and the USA too, so people who live outside those regions might find them useful for purchasing store-exclusives across several countries.
An online shop which also offers a request service. Their staff are very friendly and they'll try extra-hard to take care of any special orders. They including shipping in their website prices which makes everything seem quite expensive, but the advantage is that the price you see is the price you pay; you'll never be surprised by the shipping costs later on.
Many people use CD Japan for their regular game/book/music purchases but they also offer a proxy buying service. It's not the cheapest option, but CD Japan is a well-known, reliable company and they'll be able to help purchase all kinds of things. You can also combine your purchase with regular items on their website and once they've added a special request item to their catalogue, other customers can buy it too.
I've only used their LINE sticker purchase service but they also offer general proxy buying upon request. From my experience with their LINE service, they purchase Japan-only stickers for foreigners on their behalf and transfer them instantly as a gift. It's a simple way to buy the animated Sengoku Basara stickers if you use LINE and don't have another way around the region locking.
Big In Japan
I've never used their proxy service but I can confirm that their forwarding facility is reliable, so I can vouch that they're trustworthy.
I have never used Buyee. They're related to the forwarding company Tenso, though, so if you trust Tenso's service it might be worth trying Buyee as well.
I don't completely recommend Celga. I stopped using them myself after they sent one of my orders to the wrong person! I received it in the end but I had to wait a very long time, and nobody ever apologised for the mistake. However, they're one of the most experienced proxy services around with a lot of knowledge about the industry, so please check their site and judge for yourself.
Expensive but very experienced, FDJP specialise in difficult-to-obtain items like tickets, and they're able to check physical ticket stores which people outside Japan can't visit. It's best if you understand some Japanese if you want to use them, since they don't offer much assistance with researching items.
I have never used Rinkya. They're another of the older services with an established reputation, so check them out if you want to compare pricing. They might offer a good deal depending on where you live.
Method 2: Using a forwarding service
This option is for people who feel confident buying directly from Japanese websites. Forwarders don't offer any help with Japanese sellers; all they do is accept your parcels and ship them onwards to your home address. One of the major advantages of using forwarding is that you buy things in your own name and you'll earn loyalty points on many Japanese websites.
The way forwarding works is that you open a free account on the forwarding company's website and copy down the special Japanese address they give you. You then go ahead and buy your items on any shopping website you like, using your real name and the special forwarding address as the delivery address. Once the package is delivered, the forwarder notifies you and requests payment of their forwarding fees and shipping costs. Finally, they ship the item to you internationally.
The kings of the forwarding business. Tenso's service is reliable and they've improved their fees a lot over the years, finally offering cheaper shipping for customers who don't want an express service. They process large numbers of orders and have built up relationships with several Japanese stores. They recently started offering a proxy service too (see above).
Big In Japan
Another company I have used several times and they've always performed very well. Their system is less advanced than Tenso's automated checkout but they have never made a single mistake. They also offer a separate proxy service.
I've never used this company but I've heard positive reviews from others.
Japan To Door
I've never used this company either but again I've heard positive reviews from others.
Another company I have never used. A commenter has noted that they use a points system for payments which might make them less appealing.
For the specific example of ordering Sengoku Basara 4 Sumeragi - since it's the original reason I wrote this list - please make very sure you give your chosen proxy service the following special instructions to make sure you get the exact version you want:
- Whether you want the PS3 or PS4 version of the game.
- Whether you want the standard version, the 21-costume hobby box, the limited edition (standard version + towel) or the complete edition (21-costume hobby box + towel).
- Send them a link to the exact listing you want to buy (I'll list these here when they're available so copy, paste and check the link carefully).
- If you're buying one of the e-Capcom exclusive towel bundles, make sure you tell the proxy service which character you want on the towel. If you want extra towels, request those at the same time and link them to this page with the instructions.
- If you're ordering before the early reservation deadline on 24th May 2015, tell the company that you need them to order immediately and send you the 'Sumeragi ID' code they'll receive after placing the order. They need to send you the link as quickly as possible so you don't miss the registration period. Show them this link so they can read the full details about how the Sumeragi ID system works.