points directly in front of the general, and to leave the other advisor and elephant in their starting positions, to the side of the general. In this setup, the advisor-elephant pairs support each other, and the general is immune from attacks by cannons. Losing any of the pieces makes the general vulnerable to cannon, and the setup may need to be abandoned. The defender may move advisors or elephants away from the general, or even sacrifice them intentionally, to ward off attack by a cannon. Long sequences of checks leading to mate or gain of material are common both in chess compositions and in actual play. A skilled xiangqi player would often have to calculate several steps, or even tens of steps ahead for a forced sequence. In the diagram on the right, Black has an immediate mating threat which cannot be parried, forcing Red to check Black on every move. Although it requires 11 moves to mate, its general idea is clear: Induce a smothered check by sacrificing a chariot at the centre of the palace (e9), then force Black to open the centre file, enabling the Red general to assist the attack, and finally mate by facing generals. Openings Since the left and right flanks of the starting setup are symmetrical, it is customary to make the first move on the right flank. Starting on the left flank is considered needlessly confusing. The most common opening is to move the cannon to the central column, an opening known as 當頭炮 (trad.) / 当头炮 (simp.) dāng tóu pào or "Central Cannon". The most common reply is to advance the horse on the same flank. Together, this move-and-response is known by the rhyme 當頭炮，馬來跳 (trad.) / 当头炮，马来跳 (simp.) . The notation for this is "1. 炮 (32)–35, 馬 (18)–37", "1. C2.5 H8+7", or "1. Che3 Hg8" (diagram at right). After Black's 1. ...H8+7 (Hg8) response, the game can develop into a variety of openings, the most common being the 屏風馬 (trad.) / 屏风马 (simp.) or "Screen Horses (Defence)" in which Black develops the other horse to further protect his middle pawn (...H2+3 or ...Hc8) either immediately on his second move, or later when Black transposes the game into this opening. Alternative common first moves by Black are developing either cannons (1. ...C8.5/1. ...Che8, or 1. ...C2.5/1. ...Cbe8); note that after either of these moves, taking the central soldier with the