Anyone curious to know how months of simmering diplomatic tensions between Japan and China are playing out in real life need only have dropped by Beijing’s Worker’s Stadium on Wednesday night to watch Beijing’s Guoan soccer club take on Sanfrecce Hiroshima in AFC Champions League group play.

The Champions League tournament, organized by the Asian Football Confederation, features the top 35 sides from the top 10 Asian leagues. In Wednesday’s showdown, Guoan put on an impressive display of offense, battering Hiroshima’s keeper with a barrage of dangerous shots on the way to a 2-1 win.

But the more stirring firepower stood outside the stadium walls, where columns of police and paramilitary soldiers outfitted with body armor and riot shields were lined up solemnly in front of troop transport vehicles, with other columns stationed along the road leading away from the stadium and in the nearby upscale Sanlitun Village shopping center.

Such a large police presence was remarkable even in a city that’s no stranger to heavy security, and was all the more noteworthy for coming at a time when security forces were already deployed elsewhere in the city to protect leaders attending the country’s annual parliamentary meetings.

Authorities had reason to be nervous. A diplomatic standoff over the disputed Diaoyu Islands in the East China Sea referred to as the Senkaku Islands in Japan set off violent protests in cities around China in August and September in which at least one Chinese man was killed for driving a Japanese car.

More recently, China ruffled feathers in Japan by refusing to attend a ceremony marking the two-year anniversary of the Fukushima nuclear disaster because Taiwan was attending as an independent state.

The area around Worker’s Stadium features a number of clubs and restaurants and is typically a festive place, but as fans poured through the gates at 7:00 pm for the game, the police presence and a helicopter buzzing overhead contributed instead to a vague atmosphere of menace.

Once inside Guoan’s infamously foul-mouthed fans resorted to their conventional profanity-tinged chants and an early goal from the Beijing side lifted spirits, though tension returned after Hiroshima tied the game and a series of hard fouls followed.

A small contingent of Hiroshima fans was isolated at a far end of the stadium, kept separate from Guoan fans by many columns of empty seats and a ring of police.

Though sports victories spur rioting almost as frequently as defeats, Guoan’s winning goal sent the crowd home seeming relaxed. Many fans, with spirits high, stopped outside the stadium to pose for photos in front of the riot police, who appeared unmoved by the happy fans popping peace signs.

周三晚间，工人体育场上亚冠联赛小组赛北京国安对阵广岛三箭的比赛中，广岛三箭的一小群球迷被单独安置在工体的一个角落里。

中日两国数月来蓄势已久的外交紧张局势会如何影响现实生活？对此感兴趣的人只需周三晚上到北京工人体育场，观看亚洲足球俱乐部冠军联赛(AFC Champions League)小组赛北京国安对阵广岛三箭(Sanfrecce Hiroshima)，就能有所发现了。

由亚足联(Asian Football Confederation)主办的亚冠联赛包括亚洲10大联赛的35支队伍。在周三的比赛中，国安大打攻势足球，多次有威胁的射门令广岛三箭的守门员应接不暇，最终以2:1取胜。

不过，更令人不安的“火力”出现在体育馆之外。一队队身穿防弹衣、手持防暴盾牌的警察和武警庄严肃穆地站在运输车前，还有成队的人驻守在通往体育馆的道路沿线和附近的三里屯购物中心。

即使是在严密的安保措施司空见惯的北京，出动如此大规模的警力也实属不平常，尤其是在北京其他地方已经部署了大量警力保卫参加两会的领导人安全的时候，这一做法更值得注意。

当然，有关部门是有理由感到紧张的。中日在钓鱼岛（日本称尖阁列岛，Senkaku Islands）上的外交对峙去年8月和9月曾引发中国内地城市出现暴力抗议活动，至少有一名中国男子因驾驶日本车而被杀。具有领土争议的钓鱼岛位于东中国海(East China Sea，中国称东海)。

前几天，中国因台湾以独立国家的身份出席福岛核灾难两周年纪念仪式而拒绝出席。日本对此颇为不满。

工体周围有很多俱乐部和餐馆，是个适合大家聚会的地方。但由于球迷们在晚上7点为观看比赛而鱼贯入场，大规模的警力部署和头顶上轰鸣的直升机让人感觉有一种说不清道不明的危险气氛。

国安球迷向来以说脏话而为人所知，他们一入场便喊起了带有粗话的传统口号。随后，国安先入一球更是令全场群情激昂，不过在广岛三箭扳回一球以及出现一连串恶意犯规后，气氛再次紧张起来。

支持广岛三箭的一小群球迷被单独安置在工体的一个角落里，与国安球迷之间隔着很多空座位和一些警察。

虽然体育赛事的胜利几乎同失败一样，都能引发骚乱，但国安的致胜进球却让中国球迷看似很轻松。很多兴致极高的球迷在体育场外以防暴警察为背景驻足拍照，而那些警察好像并没有被那些比着V字手势的快乐球迷所打动。