14:38 - The early leader is Hyunsub Kim of South Korea, but he's primarily just the face at the front of a huge pack.

14:40 - Minor tragedy at the first water station: one of the Brazilian entrants, Jose Alessandro Bagio, is sitting on the course and sobbing in frustration. It's unclear what happened to him. 8:13 for 2km, Kim still leading with a 3s lead. It's not uncommon for athletes to arrive at an Olympic final injured and start races they otherwise might not, hoping for an Olympic miracle.

14:43 - Lead change: Matsunaga of Japan to the front. Kim was warned, which may have made him more cautious. Nearly everyone is still in contention, though.

14:48 - 16:15 at 4km, now with Tom Bosworth in the front. Bosworth's closest pursuer, Samuel Gathimba, is the African champion (16:16). More than 50 walkers are within 15 seconds of Bosworth at 4km, so there are plenty of names still in contention.

14:57 - 24:12 at 6km. Bosworth in front, Gathimba 2s back, and then Ben Thorne, last year's bronze medalist at the world championships, leading the main pack another two seconds behind Gathimba. The overall pace has slowed a bit but we're still seeing some DQs  (Lukas Novak - POL and Gurmet Singh - IND)as athletes strain to keep up. Thorne is visibly grimacing occasionally. Much of the challenge of the walks is in the effort of maintaining legal form as the fatigue of the race mounts.

Dzianis Simanovich (BLR): DNF

15:04 - Demonstrating that challenge: Gathimba has drawn even with Bosworth now (32:13 at 8km) and was immediately warned. Walking fast is much harder than it looks.

15:07 - Thorne still leads the pursuit, five seconds back at that split, but things are changing again. Bosworth is leaving Gathimba behind and trying to expand his lead.

Andres Chocho (ECU) is the third DQed.

15:10 - Andres Chocho (ECU) is the third DQed.

and fourth DQ is Ganapathi Krishnan (IND)

15:12 - The DQ of Andreas Chocho of Ecuador is a significant loss to the field. Bosworth still leads, 40:10 at 10km. Matsunaga is now five seconds back from Bosworth. Follows: Dane Bird-Smith, Whang Zhen, Inaki Gomez, Cai Zelin and others (40:22). The last time Britain won a medal in the 20km walk was 1964, when Ken Matthews won gold.

15:16 - Matsunaga is up on Bosworth's shoulder now. The Battle of Bosworth has been re-joined.

15:22 - 48:06 for Bosworth at 12km. Cai has caught Matsunaga but not dropped him.  They are followed by Inaki Gomez and Benjamin Thorne (CAN) Wang Zhen Dane Bird Smith in 48:17)

15:31 - 14Km: leader is Cai Zelin (56:08) in front of Bosworth, Gomez, Wang, Bird Smith (56:10). Quentin Rew (NZL) is the fifth DQed

15:36 - 16 km - Seven to lead: CaI Zelin, Dane Bird Smith, Wang Zhen, Caio Bonfim (BRA). Inaki Gomez, Daisuke Matsunaga and Manuel Esteban Soto (COL) all in 1:04:06. World Champion Miguel Angel Lopez (ESP) is 15th (1:04:34).

15:41: 17 km  - Things are getting interesting with 3km to go. Wang has taken the lead from Cai and is making a break for victory. Dane Bird-Smith is following Cai.

15:45 - 18 km: That's Zhen Wang (1:11:48) in the lead. He won in Rome earlier this year and was second last year at the IAAF World Championships in Beijing.

Second Cai Zelin (1:11:52), third Dane Bird Smith (1:11.50), fourth Caio Bonfim (1:12:00) together with Christopher Linke (GER).

Matteo Giupponi (ITA) is 10th in 1:12:29.

15:49 - Possible drama: Bird-Smith's challenger for bronze is Brazil's Caio Bonfim, who may be the crowd favorite.

15:50 - Wang Zhen won gold in 1:19.14, Cai Zelin Silver in 1:19:26, Dane Bird Smith bronze in 1:19:37.

Fourth Caio Bonfim (1:19:42 - new national record).

Fifth Christopher Linke (GER) in 1:20:00

Sixth is Tom Bosworth (GBR) in 1:20:13

Seventh is Daisuke Matsunaga (JPN) in 1:20:22

Eight with new personal best a wonderful Matteo Giupponi (ITA) in 1:20:27. Congratulations to him and his coach Gianni Perricelli.

Congratulations to Sandro Damilano coach of Wang Zhen and Cai Zelin. 
Other two medals to his palmares.

Full results and split times of three races: click here

Photo album by Giancarlo Colombo and others : click here

(from the IAAF Website by Phill Minshull)

Despite the presence of reigning Olympic and world champions Chen Ding and Miguel Angel Lopez in the field, the pre-race favourite on current form was China’s Wang Zhen and the winner at the IAAF World Race Walking Team Championships in Rome back in May didn’t disappoint.

He pulled away from a seven-strong leading pack at 17 kilometres and quickly established a lead which proved to be insurmountable before winning in 1:19:14.

His strategy was a mixture of astute championship racing and pure gambler’s luck.

Great Britain’s Tom Bosworth was the leader for much of the first half of the race, edging to the front just before the 4km mark and then laying down the gauntlet for everyone to follow.

Initially, he was tracked by Kenya’s 2016 African champion Samuel Gathimba who followed him a few strides behind until just before 8km, when he got on the Briton’s shoulder.

However, Gathimba was to start struggling soon afterwards and drifted backwards rapidly before dropping out just after 18km.

Bosworth passed the halfway point on his own in 40:10 with Japan’s Daisuke Matsunaga coming out of the chasing pack and passing 10km five seconds in arrears, with the 22-strong group another seven seconds further back.

Notable at this point was that Chen Ding was almost certainly not going to retain his title or even get on the podium.

The 2012 Olympic gold medallist had looked uncomfortable in the leading pack for several kilometre and in the 10th kilometre had got detached and was trailing six seconds off the back of the main pack and down in 26th place.

Astute observers would have also noticed that Lopez looked far from his usual calm and controlled self and was hanging on grimly at the very rear of the challenging group.

Over the next two kilometres, Bosworth speeded up and was under eight minutes for the next 2km split around the Pontal course but Matsunaga was walking even faster and had closed the gap to two seconds, while China’s Cai Zelin decided to protectively cover the two men in front of him and had pushed hard to remove himself from the pack.

Rome silver medallist Cai continued to motor and overtook Matsunaga and then Bosworth but the pack also started to increase their pace, consuming Bosworth and Matsunaga just before the 14km checkpoint and Cai shortly after, making it a 12-man massed together entering the final quarter of the race.

The pack – which also contained local hope and Brazilian record holder Caio Bonfim, who was getting rousing cheers every step of the way – was reduced to nine over the next lap with Cai, whose cadence can best be described as a resembling a boxer doing his road workout, pushing the pace at the front.

Wang picks his moment 

This remained the state of affairs until Wang, a much more fluent and elegant walker than his team mate, made his decisive bid for glory with three kilometres to go.

He quickly put four seconds between himself and the chasers, still led by his compatriot Cai, with the penultimate lap taking just 7:42, the fastest split of the race at that point.

This was just a prelude to what Wang was able to unleash over the final 2km, a split of 7:26, which Cai had no way of countering.

After Wang had crossed the line in 1:19:14, Cai came home 12 seconds later, the winner having put an additional eight seconds between himself and the man in second place over the final 2km.

Coming home third was an utterly delighted Dan Bird-Smith who managed to pull away from Bonfim over the final 1km lap to take the bronze medal in a personal best of 1:19:37.

The evidence of what getting a medal meant to Bird-Smith could be seen barely a minute after he crossed the line when the realisation that he would be on the podium led to him start to sob uncontrollably on the shoulder of Bosworth.

Bonfim missed out on what would have been a memorable medal by five seconds – the highest any Brazilian walker of either gender had finished before at the Olympics was 14th – but he had the consolation of setting a national record in 1:19:42.

Germany’s Christoper Linke finished fifth in 1:20:00 with the early leader Bosworth finishing a hugely commendable sixth in a national record of 1:20:13.

Further down the field, Miguel Angel Lopez got something of a second wind and finished 11th while Chen was down in a disappointing 39th place, more than four minutes behind the winner.

Phil Minshull for the IAAF