All at once, the markets for pork, other agricultural products and iron ore face distortions, and China might be willing to accept yuan appreciation to protect against the resulting commodity-related inflationary pressures.

With global growth predicted to slow, oil prices are expected to drop. However, disruptions to oil supply due to factors such as US sanctions on Iran and Venezuela, and rising electricity consumption in China, could cause a rise in prices.

While the US dollar is expected to weaken against the renminbi, its surprising strength against the euro and yen – the result of the Fed’s dovish turn and US Treasuries’ attractiveness viz-à-viz euro-zone and Japanese government papers – is bad news for Beijing.

The Bank of Japan, which has for years been trying to lift the economy out of a deflationary spiral, is unlikely to tolerate a rising yen and will act if it has to.

Expect China’s fiscal loosening and foreign investment reform to lift the yuan, especially as the effects of US stimulus from last year continue to wear off and a trade war settlement looms.

Major economies around the world, from Canada and Japan to the euro zone and Australia, reserve the right to let currencies depreciate if conditions weaken. China should not give up its right to do the same as part of any trade war settlement.

China may well accept a trade deal that specifically calls for a stronger yuan, while investors will look to buy more of the currency to fund increased holdings of A-shares.

It is one thing for Washington to call on Beijing to stabilise the yuan; quite another for it to insist on a strong Chinese currency when it relies on the weakness of its own dollar.

Despite Huawei’s leading role in the field, security concerns mean the US was certain to oppose the Chinese firm’s involvement in the roll-out of 5G tech – and Washington won’t be alone.

The US central bank’s position has softened and, with other currencies set to decline or hold firm, the yuan suddenly looks like a good bet to rise in value.

If China accedes to US pressure to strengthen the yuan against the dollar, it would also result in a rise in the yuan’s value vis-à-vis the euro. This would be unpalatable to Chinese exporters and a blow for the euro zone.

The timing seems right for a deal between Washington, where worries about Trump’s 2020 prospects are beginning to bite, and Beijing, which can do without the distraction of a trade war as it focuses on economic reform at home.

Despite the Chinese currency’s strong start in January, the uncertainty over US-China trade negotiations and the possibility that Chinese exporters were behind seasonal demand for the yuan should give investors pause.

Last week’s ‘flash crash’ that sent the yen soaring showed the currency’s draw when the jitters hit. Continuing market pessimism about the US and Chinese economies, and Japan’s own 2019 outlook, may add up to a good year for the yen.

It is prudent to have both concerns and confidence regarding China’s economy in 2019, as reforms and trade negotiations continue and policy options can still lift prospects.

Investors hoping for a quick resolution of the current stand-off over trade should brace themselves for a protracted conflict, as both countries compete to protect their technological edge and strategic interests.

The yuan might not weaken, despite China’s slowing economy and the trade war. Foreign exchange is relative. For the yuan to weaken, the market would also be making a judgment about the appeal of other currencies.

The dollar’s strength has widened the trade deficit by making US exports more expensive and goods it imports cheaper, defeating a purpose of Trump’s tariffs.

Investors can adjust short-term plans, but the pending US tariff hike has only been delayed for 90 days. And, even if the trade war is resolved for good, investors may have to prepare for more Fed rate rises than expected.

Market watchers are on the alert for a slide in the US dollar, and Asian currencies may be the ones to benefit when the time comes, although that may not be before 2019.

Lower prospects for the Chinese economy did not directly cause the recent drop in oil prices. However, US waivers on its new Iran sanctions for China (and others) signalled the collapse of a central pillar of support, leading to fear in the market.

The Federal Reserve’s determination to raise rates and roll back quantitative easing means the dollar is unlikely to weaken. Combine this with weak Chinese economic data, especially concerning autos and homes, and there is reason to anticipate further declines in the yuan.

Neal Kimberley says the China-US dispute, from tariffs to intellectual property and Taiwan, runs so deep and the US is feeling so good about its position that one Xi-Trump meeting can’t possibly end it.

Worries about the US-China trade war are fuelling demand for the yen, strengthening the currency to Japanese exporters’ dismay.

• Debt risk and slowing growth are putting downward pressure on the yuan, and officials are hinting they won’t stand in the way of devaluation

By squarely blaming China for the weakness of the yuan and insisting it follows a ‘market-determined currency regime’, the US may have misread the likely consequences of China loosening its grip and shedding its capital controls.

US sanctions on Iran are driving up oil prices for Asian countries with weaker currencies. China and Hong Kong should be able to cope, but India and Indonesia are already suffering.

Now Beijing recognises that Trump’s tariff moves – though in the name of fair trade – stem from a change in America’s strategic intent, it, too, is rethinking the bilateral relationship. Neither side is likely to want a return to the old status quo.

Not only is gulf of disagreement between the two too wide to bridge, but neither side is focused on finding a fix: US attention is trained on the larger picture of China’s rise, while Beijing is working to reflate its economy to offset the impact of the trade war.

An intensification of the China-US trade war, combined with Federal Reserve monetary tightening, could spell double trouble for currencies in the Asian region.