The Double Dangerous Book for Boys. Conn Iggulden

on black. It is an opening for players who like to play white aggressively.

      1 Pawn d2-d4, answered by black’s pawn d7-d5. So far, nothing too shocking.

      2 White moves pawn c2-c4 – allowing it to be taken by the black pawn.

      The idea is to develop white rapidly, at the expense of a pawn, while black loses a move of its development to take that pawn: ‘Queen’s Gambit Accepted’. It’s a trade-off and it’s risky. White will then reply by moving the pawn on e2-e3, which defends the pawn on d4 and attacks the black pawn. It’s not easy for black to protect that pawn and it mucks up his whole development trying.

      However, black can also defend that pawn on d5 with a pawn to e6. White can then exchange pawns. The Queen’s Gambit is an interesting opening and well worth including in your range.

       THE NIMZO-INDIAN DEFENCE

      So far, we’ve dealt with white openings, but, of course, there are also black openings – defences. The Nimzo-Indian Defence (developed by Aron Nimzowitsch 1886–1935) is a good example of the class of black openings known as ‘Indian’ defences. They were first developed by Moheschunder Bannerjee in the 19th century. The Nimzo-Indian, Bogo-Indian and Queen’s Indian are all in response to a pawn d2-d4 opening by white.

      1 Pawn d2-d4 by white. Black responds with Nf6 – knight to f6.

      2 Pawn c2-c4 by white. Black moves pawn e7-e6.

      Those two exchanges are the opening moves of all ‘Indian’ defences. The Nimzo variation looks a little bit like the Ruy Lopez attack.

      3. If white moves Nc3 – knight to c3 – black can bring the bishop across to pin the knight. The white attack has been disrupted. Black usually takes the knight on c3, for the advantage of doubling white’s pawns.

      Indian Defence

      Nimzo-Indian Defence

       THE SICILIAN DEFENCE

      This defence begins from an e2-e4 pawn opening by white. Instead of the standard response of e7-e5, black responds with c7-c5, attacking from the c file.

      This is known as the Dragon Variation, as the black pawns are said to look like a dragon.

      1 Pawn e2-e4, Black responds with c7-c5.

      2 White knight moves: Nf3. Black moves pawn d7-d6.

      3 White moves pawn d2-d4. It is taken by black’s pawn: c5 x d4.

      4 White takes the black pawn: N x d4. Black is still developing and moves: Nf6.

      5 White moves up second knight: Nc3. Black responds with pawn g7-g6.

      Sicilian Defence after two opening moves

      Further developed: five moves

      The Najdorf Variation of the Sicilian Defence was one often used by Bobby Fischer. It is exactly the same until move five, when instead of the g7-g6 pawn move, a pawn is moved a7-a6 instead. There is also an attack on the foremost white knight with the black pawn move e7-e5.

      You get better at chess by playing, but also by learning successful strategies. Get to know these. Use them as often as you can and enjoy the games that result.

       GREAT BRITISH TREES

      David Pearson/Alamy Stock Photo; Inset. Kefca/Shutterstock.com

      There is a chapter on trees in the original Dangerous Book, but despite astonishing variety, we managed to include only eight: the oak, the lime, the hawthorn, the silver birch, the beech, the horse chestnut, the sycamore and the ash. They are good ones, but space prevented the inclusion of more – something we can remedy with another six here, bringing the total to fourteen. With thanks to the Woodland Trust, a charity that protects ancient woodland and plants new ones.

       YEW

       Taxus baccata

      Evergreen and extremely long-lived, with dense foliage that can be shaped into a hedge. Highly poisonous and traditionally believed to ward off evil spirits, which is one reason why they are often planted in churchyards. Ancient yews are slightly eerie to encounter. The most famous use of their wood is in the longbows of English and Welsh archers, so they have a powerful historical association.

       WILLOW

      Not only are cricket bats, baskets, fences and chairs made from flexible willow, but its bark contains salicylic acid, which is better known as aspirin. It was the world’s first painkiller and anti-fever agent. For that alone, it would be a wonder – but also, see cricket bats. The two most common varieties are the crack willow (Salix fragilis), which has twigs that break with a crack sound, and the white willow (Salix alba), which has pale undersided leaves and more flexible twigs. Usually found near water.

      Müller/McPhoto/Alamy Stock Photo; Inset. Florapix/Alamy Stock Photo

       LONDON PLANE

      Worth including here as it is found in every London park and places such as Berkeley Square, though few other places. It is not a native breed, but a hybrid of the Oriental plane (Platanus orientalis) and the American plane (Platanus occidentalis) – imported in the 16th and 17th centuries respectively. Distinctive speckled bark. Planted in huge numbers in the 19th century to help soak up pollution. Sometimes called the ‘lungs’ of London.

      Mark Zytynski/Alamy Stock Photo; Inset. Manor Photography/Alamy Stock Photo

       ROWAN

       Sorbus aucuparia

      Known to the Greeks and sacred to the druids, this ancient British tree hangs heavy with red berries when all else has gone to winter. The berries are inedible in large quantities to humans, but loved by birds. The trees have been associated with protection and magic for thousands of years. They were often planted near houses to keep witches away. One friend of ours has rowan trees on three sides of his house, but cannot prevent his aunties getting in through the front door.

      Geoff Smith/Alamy Stock Photo; Inset. FLPA/Alamy Stock Photo

       SCOTS PINE

       Pinus sylvestris

      Ancient pine with blue-green needles. Native to Scotland and found mainly in the Highlands. Adopted as the official tree of Scotland in 2014, they can grow to 120ft tall (36m). They are home to red squirrels, wildcats, pine martens, owls and capercaillies – the largest member of the grouse family. As with oaks, each mature tree is a village.

      Arterra Picture Library/Alamy