The new Nations Championship launches with northern and southern hemisphere teams facing off in a novel format. Six Nations sides England, Ireland, Scotland, Wales, France and Italy compete against southern powerhouses South Africa, New Zealand, Australia and Argentina, plus invited teams Fiji and Japan. Each side plays six cross-hemisphere matches across July and November, with play-offs culminating at Twickenham's Allianz Stadium.

Historically, southern hemisphere teams dominated, winning nearly 57% of Tests over 125 years. South Africa's apartheid-era boycott briefly shifted momentum, while Fiji and Japan struggled early against northern opposition. The south's professional revolution and New Zealand's golden generation extended their advantage, but recent years have seen a dramatic rebalancing. Ireland's emergence as a superpower coincides with Australia and New Zealand's decline, creating an almost 50:50 split this decade.

Tactical evolution favors longer ball-in-play periods, with tests averaging two and a half extra minutes compared to 2021-23. Northern teams kick 80 metres further but tackle 25 times more per game. Southern sides recycle ball 10% faster and gain 18% more post-contact metres. Ireland's Joe McCarthy leads form ratings at 8.5 out of 10 across five matches, followed by Jordie Barrett and Tommy Freeman.

With club seasons concluded and players arriving in peak condition, this tournament represents rugby's most compelling north-south rivalry in decades. The format's dual championship structure - individual and hemisphere titles - adds strategic complexity rarely seen in international rugby.