Shey dis na di week wey di war go dramatically turned in favour of Ukraine? Na ogbonge moment as coalition of Western nations confirm say dem dey willing to supply modern-made main battle tanks.

Germany tok say dem go send Leopard 2 tanks and US say dem go send M1 Abrams tank. Both di UK and Poland don already make concrete pledge and oda nations dey expected to follow. Some commentators don describe di move as potential “gamechanger”.

Ben Barry wey be senior fellow for di International Institute for Strategic Studies (ISS) tell BBC say Western tanks fit make a difference. But di former British Army Brigadier also warn say di pledges fit no prove decisive.

For modern warfare, tanks na key element for offensive operations to punch through enemy lines and take back territory.

If dem use am effectively, dem dey provide mobile firepower, protection, shock and surprise. Dem fit dislocate enemy defence. But dem also need di support of artillery to first weaken di defence and den di support of infantry to hold retaken ground.

History show say tanks alone no dey win battle. Di British first use hundreds of tanks for di battle of Cambrai for November 1917 to end di deadlock of static trench warfare. Dem bin make correct advances but many tanks come begin break down and German counter offensive turn British gains to losses.

Dem fit also use tanks for defence. For 1940, di retreating British and French armies for Arras use di tanks to stall di Nazi invasion. Dis allow di evacuation of British troops from Dunkirk.

But Ukraine don make am clear say weapon wey dem need no be to just stall any potential spring offensive, but dem wan retake dia own territory - to go on di attack.

How Ukraine fit use tanks lead attack

E go make little sense for Ukraine to send dia additional tanks across frontline of more dan 1,000km (621 miles). To break through Russian defences, Ukraine gazz concentrate dia forces – maybe ova an area of between five and 20km (between three and 12 miles).

Hamish de Bretton-Gordon wey be former colonel for di British Army Royal Tank Regiment say numbers dey important for breakthrough. Armoured brigade for significant offensive operation go normally include at least 70 tanks. So more dan 100 Western battle tanks fit make big difference, e tok.

If Ukraine get more, dem fit try to conduct offensive operations wey go happun for different places at di same time, as dem do last year for di north and di south.

Den additional support gatz dey for wetin di military call "combined arms manoeuvre".

Di UK no just dey send Ukraine 14 Challenger tanks, dem also dey send 30 artillery self-propelled guns and armoured vehicles to carri and protect troops.

Dat new package of military support also include mine breaching and bridge-laying vehicles. In oda words, di essential elements wey dey needed for any offensive operation.

Di US dey also provide Ukraine wit more dan 100 Bradley and Stryker armoured vehicles, and Germany dey provide 40 of dia Marder infantry fighting vehicles and tanks.

Tanks na di tip of di spear. Dem design am to move quickly ova open ground. Di Challenger 2, Leopard 2 and M1 Abrams dey faster dan most Russian-made tanks wit speeds of more dan 25mph (40km per hour) on rough terrain.

To take ground quickly, wit any element of surprise, dem go likely avoid urban areas where dem go dey more vulnerable to attack. Wen di war first start and in dia failed attempt to surround Kyiv, Russia show say long column of armour for road na easy target.

Oga Barry of ISS say any spearhead attack go look for enemy weak points. But e also warn say Russia don spend di last few months reinforcing defensive positions wit trenches and tank traps.

Western tanks also dey about 20 tonnes heavier dan di Russian own. Di additional armour give better protection but e also mean say di tank fit dey more heavy to cross some makeshift bridges. Russia and Ukraine don blow bridges to slow down advances.

Surprise attack for night

Oga de Bretton Gordon, wey command one British Challenger squadron of tanks, say one of di big advantages of Western-made tanks na dia ability to fight for night.

Night sights and thermal imaging camera na standard. Only Russia more advanced tanks - like di T-90 – dey fit to fight for night. Attacks under di cover of darkness also add to di element of shock and surprise.

Di greatest challenge for Ukraine go be logistics - maintaining di flow of fuel, ammunition and spare parts. Ukraine dey worry about many complex inventory of Western supplied weapons.

Britain Challenger 2 tanks, for instance, no dey use di same Nato standard ammunition as di Leopard and Abrams. Di Challenger 2 no dey for production again and even di British Army tok say dem don use some spare parts from di existing fleet for anoda weapon.

Oga Barry say Ukrainian engineers fit dey familiar wit repairing diesel engines - like di one for Leopard and Challenger. But he say di US-made Abrams run on more complicated gas turbine engine. E also consume about twice di amount of fuel as a German-made Leopard.

If Western pledges go well, Ukraine Armed forces fit dey boosted by more dan 100 tanks. E still no reach wetin Ukraine overall military commander bin ask for.

Last October, General Valerii Zaluzhnyi say Ukraine need additional 300 tanks, 700 infantry fighting vehicles and 500 howitzers for dia offensive dis year. E fit end up wit just half of dat.

Di training wey di weapon require go take time too - weeks if not months. And e still neva dey clear wen all dis equipment go arrive.

Di US don indicate say dia 31 M1 Abrams tanks fit no dey readi for months. Ukraine dey also wait for di West to respond to dia repeated request for modern warplanes. An army attacking on di ground go need protection from di air.

Western officials bin hope say Ukraine fit dey able to mount offensive as soon as dis spring. Dem believe say opportunity dey while Russia dey struggle to recruit and rebuild dia battered forces, and to add to dia supplies of ammunition wey dey go down.

Ukraine don manage to prove pipo wey dey doubt dem wrong - but dem go still need more Western support if dem wan achieve dia goal of expelling Russian forces.