Shikoku (四国) is an oft-forgotten island in Japan. The smallest of Japan's Big Four, it lies to the south of Honshu. The island is thought of as a rural backwater, with few must-see attractions, but a visit there can wash away those doubts; the mountainous inner regions offer some good hiking. It is also the home of the 88 Temple Pilgrimage of the Shingon sect of Buddhism.
Shikoku literally means "four countries", and it indeed consists of four ancient countries (now prefectures) on Shikoku island, conveniently arranged around the compass points. Each prefecture also has an old provincial name, still often found in place names and listed in parenthesis below.
Shikoku is a primarily agricultural island, renowned for its citrus fruits. Cutting through the centre of the island is the mighty Yoshino river whose clear waters and big turbulent rapids make for great rafting.
Shikoku is far enough off the beaten track that some Japanese ability, while not absolutely necessary, will come in handy. Some of Shikoku's dialects, notably Tosa-ben spoken in Kochi, are famously incomprehensible even to other Japanese.
While there are highways linking Shikoku with Honshu, they are expensive -- around ¥5,000.
Prefectural capitals Takamatsu, Matsuyama, Kochi and Tokushima all have small regional airports. Matsuyama has flights to Seoul and Shanghai, while Takamatsu fields a few flights a week to Seoul. For any other international destinations, you will likely have to connect via Tokyo or Kansai.
Shikoku is not connected to the Shinkansen network, but there are frequent connections from Okayama on Honshu to Takamatsu and from there on throughout the island. The limited express Shiokaze (特急 しおかぜ) runs back and forth betweeen Okayama and Matsuyama roughly every hour during the day, skipping some stations on the way, if you feel like a more direct connection to that side of the island. The pace on Shikoku being what it is, don't come there expecting any of the trains to be super fast. It would also be wise to remember that train information will be in Japanese only, unlike what you may be used to from the Shinkansen. So either be sure to brush up on your knowledge of terms such as "unreserved seats" and the names of the places you're planning to visit, in kanji, or plan to ask a lot of people (which may be more fun, but may also take more time).
There are numerous ferries that run to Shikoku that can be taken from major cities like Kobe and Hiroshima. From Hiroshima to Matsuyama expect to spend 2700 yen. The ferry takes around 2 and a half hours.
The JR train network connects the larger towns together fairly well, but regular trains are slow and expresses are expensive. The main lines are:
For heavy travel, JR offers the Shikoku Free Kippu (四国フリーきっぷ) , which allows unlimited usage of JR trains and buses, including limited expresses, on three consecutive days (¥15,700). If you manage to time it so that you can start on your birthday, ask for the Birthday Kippu instead, and you'll get the same deal for just ¥10,000!
For the frugal traveler, the Shikoku Saihakken Haya-Toku Kippu (四国再発見早トクきっぷ )  may be a better deal, as it offers one day of unlimited travel for just ¥2,000. There are three big catches though: it's only valid on weekends and public holidays, it's limited to local trains, and you have to buy it at least one day in advance.
There are some other minor lines with infrequent trains. Some parts of the JR network, notably the southern segment from Kubokawa to Sukumo, have split off to the private Tosa Kuroshio Railway company.
Serious pilgrims may choose to complete the 88 Temple Circuit (see Do) on foot.
There aren't any "Shikokuan" foods per se, but each prefecture has something that they're famous for: