With the financial jury still out on the recovery of Japan's economy, Euromonitor International reports that online travel is set for eye-watering levels of growth over next five years, at the expense of offline channels.
The key headline finding from the executive summary of the Travel Retail in Japan 2014 report is that:

Travel retail is expected to post a 1% CAGR in terms of value sales at constant 2013 prices to reach ¥8.1 trillion (£47 billion) in 2018. Travel retail online sales are expected to grow by an 18% CAGR to take share from travel retail offline sales.
An 18% growth for online compared with 1% for the overall market over the next five years is impressive. In terms of share, however, it is lagging - online sales in Japan in 2013 were worth ¥1.5 trillion (£8.7 billion), equivalent to around 19% of the total market worth ¥7.7 trillion (£44.7 billion).
By 2018, online travel sales will be ¥3.4 trillion (£19.7 billion), giving it a 42% share of the market.
But this share still sees Japan's online travel sector lagging behind other mature e-commerce markets, suggesting that the growth story still has more legs in what is the world's third largest economy.
The sector breakdown for 2013 is as follows:

Accommodation dominated online travel retail, accounting for a 52% share of retail value sales, followed by flight (27%) and package holidays (17%).
No indication is given as to whether this will change over the next five years.
The big shift towards online is, like everywhere else in the world, driven by smartphones, tablets and mobile. While the usual suspects of Facebook, Twitter and Google + are noted as part of the marketing arsenal for online travel businesses, local offers such as Japanese-focused social network Mixi ( 27m+ users in Japan) and messaging/entertainment platform LINE (50m users in Japan) are mentioned.
In a nod to what is happening elsewhere, Euromonitor points out that the market leader in Japan, JTB Corp, is shifting "from the brick-and-mortar travel retail model to an online travel retail model." JTB has nearly 20% of the market by value.
But again, with only 10% of its sales coming from online in 2013, there is significant potential from more growth to come.
NB: Japan keyboard image by Shutterstock