The GC battle begins today on La Planche Des Belles Filles

So today's the day in this year's Tour de France. The phoney war will end and by about 4.30pm this afternoon (UK time) we will have a much clearer idea of which riders will be involved in the GC battle and which riders were only flattering to deceive.

Yesterday's 169km stage from Sainte-die-des-Vosges to Colmar saw the peloton encounter the first sizeable climbs of this year's race and today's 157km stage, which starts in Mulhouse, will see the riders tackling five climbs of category 2 or higher. The final climb to La Planches des Belles Filles is fast becoming one of the iconic climbs of the tour after it was introduced to the race for the first time in 2012.

'There are so many riders to choose from this year, anyone of about 30 could slip away and either win the stage or steal Yellow. Of course the winner could come from a breakaway, which with so many climbs on this year's stage, would have a good chance of staying away today. '

By this stage of the three previous tours to include this climb – 2012, 2014 and 2017 – the rider in the Yellow Jersey has been the rider who has gone on to win that year's tour. In 2012 it was Bradley Wiggins, in 2014 Vincenzo Nibali and in 2017 Chris Froome. Froome indeed was the winner of the 2012 stage, so had he been here on this year's tour he would have been a natural favourite to win today's stage. Instead it is his Ineos teammates Egan Bernal and Geraint Thomas who stand as favourites for today's stage. Certainly, as Thomas himself has admitted, it will suit a rider of Bernal's explosive style as in places the climb is quite steep.

This year the organisers have added an extra 1,000 metres of climbing at the top to make the racing even more intense. Another innovation is the offer of time bonuses at the top of the penultimate stage which could entice some of the favourites to attack early rather than wait until the day's final climb to show their cards. It's a welcome initiative as in recent years the leaders in the peloton have become increasingly cagey on the big climbing stages, leaving their bids for victory until the final stages of the day's racing. Of course, attacking early brings with it the risk of a rider 'blowing up' so only the bravest or those who don't really fancy their overall chances will attempt it. Nevertheless it adds an extra dimension to what should be a fascinating stage.

The rider with the most to lose today will be Quick Step's Julien Alaphilippe, who wears the Yellow Jersey. Had he not been in Yellow, it's a stage where Alaphilippe would have fancied his chances of either taking the stage victory or mopping up some King of the Mountains points earlier in the stage.

The rider with the most to gain is Jumbo's Steven Kruijswijk who, if Alaphilippe falls away, could well find himself sitting in Yellow tonight. Other favourites to be in contention on today's stage are Movistar's Nairo Quintana, UAE's Dan Martin and Mitchelton-Scott's Adam Yates, who all have the explosive style that could see them claim victory at the top of the final climb.

Vincenzo Nibali, who has a good track record on this climb, is there again this year – although he comes off the back of a hard-fought second place in the Giro D'Italia so may be lacking the fresh legs of the others.

One rider who could come good on this climb and who has a good track record at La Planche Des Belles Filles is Chris Froome's former lieutenant Richie Porte. The 34-year-old Australian has flattered to deceive since he left Sky for BMC and has been cursed with some genuine bad luck in recent Tours. Maybe this year, riding for Trek-Segafredo, it will change. However as Geraint Thomas can attest riders often experience bad luck in the Tour de France when they are riding at the absolute ragged edge of their abilities. Anyone who saw Thomas's imperious ride in last year's Tour could see that he was a rider on the top of his form and his bad luck from previous Tours seemed to be a distant memory.

Enric Mas, the Spaniard who came good at the end of last year's Vuelta a Espana, should be up with the leaders on today's stage but he tends to be more of an elegant rider in the Andy Schleck style rather than a rider with the explosiveness of an Alberto Contador or Alejandro Valverde, so I don't see him as a potential stage winner. Valverde, the world champion, is there of course this year. That final climb certainly suits him but at 39 years of age I think he may find anno domini catching up with him. Valverde will also be compromised by having to act as Quintana's super domestique in the high mountains, although knowing Valverde those roles could easily be switched if Quintana is deemed by his team not to be a true contender for the overall.

The French favourites Romain Bardet, Thibaut Pinot and Warren Barguil should all be in the lead peloton on the final climb, although Pinot has a reputation for being a poor descender so he could find himself battling to get back on the lead group on some of the hills.

One rider who's form is an unknown is Fabio Aru. Aru won the stage when it came here in 2017 but his implosion late on in that year's Tour suggests he is not the rider he once was.

Who else? Michael Woods could be a surprise stage winner. The former runner has the capacity to ride well on these anaerobic climbs and many of the peloton's leaders could be keeping an eye on his Education First teammates Rigobert Uran and Tejay van Garderen, allowing the Canadian to slip away.

In fact there are so many riders to choose from this year, anyone of about 30 could slip away and either win the stage or steal Yellow. Simon Yates? Bauke Mollema? Jacon Fuglsang? Emanuel Buchman? Mikel Landa? Of course the winner could come from a breakaway, which with so many climbs on this year's stage, would have a good chance of staying away. Maybe it will be Lilian Calmejane's year again. A good ride today – or an inspired gamble - could put any one of a number of surprise names in Yellow.

This year's Tour is shaping up to be one of the best and most open in years.

Prediction: 1) Bernal 2) A Yates 3) Porte.

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Stage 6 from Mulhouse to La Planche Des Belles Filles