In Part 2 of our series Diving in Japan, Bonnie Waycott takes us to northern Japan, and introduces ice diving off Hokkaido's Shiretoko Peninsula.

When winter arrives in Japan, it doesn't mean that you have to give up on scuba diving until the summer. Hokkaido, the country's northernmost island, may be covered in snow and ice.  Blizzards and bitterly cold winds may sweep the area frequently.  But if you're feeling brave enough to take on a new challenge, you may want to visit.  In February, frozen ice from the Sea of Okhotsk breaks up and is blown south to the Shiretoko Peninsula.  This is home to the ice diving season that begins around the end of January and lasts until mid-March.

On land, the peninsula is something else.  Designated a UNESCO World Heritage Site in 2005, it's full of national parks and a range of wildlife such as deer and bears.  In winter however, it's surrounded by ice floes.  These can be observed during a short boat cruise but if you really want to get up close to them, well this is when diving comes in.

The vast majority of people who go ice diving tend to be repeaters but new challengers are always welcome.  A good point of contact is theIruka Hotel an English-speaking dive school and hotel that can cater to non-Japanese divers.

As conditions are extreme, ice diving comes with some strict safety procedures.  Before the divers assemble for the first dive of the day, a hole is dug over the chosen dive spot and a small base is then created for assembling equipment, changing or just to keep warm.  Through the hole goes a long rope which divers are told to never lose sight of.  Because of the cold (the water temperature tends to be between 3 and -2 degrees), all dives are kept to within 10m, and usually last about 30mins.  It's essential to be familiar with your equipment, to double check your dry suit and make sure it's properly fastened.  Divers are also given special regulators that fit firmly into the mouth with a band that goes around the head, while a number of staff members from the dive school are stationed around the hole in case of emergencies.  Descending slowly and keeping a firm grip on the rope are also requirements.

Chashi-kotsuzaki, one of the area's dive sites, consists of extremely large rocks that appear at around 3.5m.  Despite the cold, it's a calm and relaxing place with crystal clear visibility and no current.  Looking around, it's by no means exciting but don't underestimate the rocks that you see.  If you're observant enough, you can spot an array of creatures - sea urchins, starfish, anemones and even a tiny fascinating green shrimp with no English name (if anyone recognizes it please get in touch!).  When you're done exploring the rocks, relax, look up and gaze in awe at the huge blocks of iceat the surface.  That's when it really hits home that you are ice diving.  The ice boulders also lend a dramatic quality to the whole experience and are a great photo opportunity.

 The highlight of ice diving is without doubt the Clione or Sea Angel, a type of sea slug that looks like a jellyfish.  Flapping its wings, it's a tiny translucent little thing that hovers under the ice like a mystical being.  It's hugely popular with divers simply because it's cute.  With its wings and cute ears, it's extremely photogenic as it makes it way through the water but it's only a tiny dot in the vast ocean - see if you can keep your eyes peeled.

If you're strong enough to brave the cold climate and want to try something different, what are you waiting for?  Don your dry suit and see what's going on under the ice!