North Korea-Trump talks in 400 words

Friday has been a landmark day in the history of the Korean tensions.

Here's your very brief guide to what has just happened

A North Korean offer

Two South Korean officials had dinner with Kim Jong-un this week in North Korea - that was itself significant.

They then flew to the US with a message from Mr Kim - he wanted to meet US President Donald Trump and was prepared to give up his nuclear weapons.

Mr Trump accepted the offer - they might now meet as soon as May.

The two leaders have hurled insults and threats at each other over the past year, like "Little Rocket Man" and "dotard".

South Korea - with which North Korea is still, on paper, at war - said this news "came like a miracle".

Why is this a big deal?

Because North Korea's nuclear weapons programme has worried the world for decades.

It has conducted six illegal underground nuclear tests and fired off numerous long-distance missiles.

It says it could hit the US with a nuke - though that's still not certain. It could definitely attack its neighbours.

Giving up the weapons would be seismic.

Why has North Korea done this now?

It's not clear. It could be that years of sanctions designed to force it to talk are working.

It could be it sees Donald Trump as someone it can manipulate.

Or it could think now is its chance to finally be recognised as a serious nuclear state.

What happens next?

Complicated diplomacy, and the clock is ticking.

We don't yet know where any talks will take place, nor who will be involved along with the leaders.

We also don't know what North Korea wants in exchange for a meeting.

North Korea hasn't actually committed to anything yet. If it does agree to throw out its nukes, the main issue will be how to prove it.

It has reneged on agreements before. As our correspondent says, it's the political gamble of the century.

Is anyone else involved?

The other main players are:

• Japan, which neighbours the Koreas. It is cautiously optimistic but wants North Korea to give up nuclear weapons before anything happens.

• China, North Korea's main financial backer. It has always pushed for everyone to talk, and said things were "heading in the right direction".

• Russia, which has a tiny border with the North. It called it "a step in the right direction".