We all know that the Oracle of Omaha is a big proponent of the long-term investment strategy. And last week, when asked about his take on investing in Japan, Warren Buffett didn't deviate from this usual strategy of finding opportunity in distress.

Here's how he put it:

Frequently, something out of the blue like this, an extraordinary event, really creates a buying opportunity. I have seen that happen in the United States; I have seen that happen around the world. I don't think Japan will be an exception.

The billionaire CEO of Berkshire Hathaway (NYSE: BRK-A)(NYSE: BRK-B) has a track record of knowing where to put his money, and when. But is his bullish take on Japan justified?

Consider that Japan had its share of troubles even before the March 11 earthquake. The third-largest economy in the world will soon find itself with outstanding debt of 200% of GDP within just a few years.

But when Buffett talks about long-term opportunity anywhere, he generally has a good reason to say so -- at least from an investment-returns standpoint. The trouble is, can we really predict the long-term future of the Japanese economy? That's much more doubtful.

Rising debt and aging demographics seriously complicate things for the island nation. And then there's that debt-to-GDP ratio, the highest in the world. Although Japan is one of the major global exporters and is running a trade surplus, I'm not sure how things will look 10 years from now. One likely scenario is that Japan is going to increase its borrowings from external sources at higher interest rates or initiate some aggressive monetary action to pay off debt.

Prime Minister Naoto Kan has acknowledged debt problems similar to some parts of Europe. The debt issue, if not contained, may have severe repercussions on various industrial sectors in the country.

Moreover, the combination of the earthquake, the massive tsunami, and the Fukushima disaster has already played havoc on the country's infrastructure. Production delays, forced shutdowns, or higher operating costs could take a fatal toll on many small to medium-sized companies. People who have invested in those companies would lose their money, insurance companies would get ravaged, and taxes wouldn't be collected. Plus, a lower production supply would mean higher prices. That spells inflation, be it for industrial or consumer goods.

All of this is seriously bad news that shapes the way that I see Japan as a long-term investment destination. However, as Buffett indicated, there are ways to think around this issue. In fact, there are several Japanese safe havens to focus on that may provide strong long-term returns. My suggestion is to invest in sectors that don't depend on the Japanese economy alone or that will help in adding value to the restructuring of the economy.

For example, do you think Nissan, Toyota (NYSE: TM), and Honda (NYSE: HMC) will continue to suffer? I don't think so. As my Fool colleague Alex Dumortier wrote in "It's Time to Buy Japan's World-Beaters!," these are companies that have a global presence. Even if their sales are affected in Japan, they can still bank on revenues from overseas markets. They might face some interruption in their operations, but it's likely that they'll bounce back to prominence as soon as the Japanese economy recovers from the damaged infrastructure. For companies such as Hitachi (NYSE: HIT), Canon (NYSE: CAJ), and Sony (NYSE: SNE), which also have a global presence, it doesn't necessarily look like a bumpy ride ahead.

Furthermore, rebuilding efforts in the country are likely to help the domestic construction industry. Companies such as Japan Steel Works, Kajima, Yokogawa Bridge Holdings, and Taiheiyo Cement will probably see a good rise in their revenue, and that will result in an increase in their stock prices.

The Foolish bottom line
The crisis in Japan has had a telling effect on the country's economy. And rebuilding isn't going to be an easy task. However, as Buffett says, there's definitely a buying opportunity here that's waiting to be tapped, if you're selective about identifying the right businesses. Whether the ones to look at are multinationals or more specific construction companies, they'll all deliver value -- just maybe not in the short term.