Everyone loves the run-in to the end of the season, it's where the business really happens, emerging from the winter darkness to find out the fortunes of your club when it really matters.The run-in for the Tigers starts now with the crucial run of games during the Six Nations.   The autumn international period earlier this season carried mixed blessings with only Ben Youngs involved in the England squad, though we also lost the likes of Ayerza, Ghiraldini and Barbieri to their own countries, and there would have been others had it not been for injury.   The Six Nations means the loss of up to six of Tigers’ England players plus the Italian duo.   Thankfully, though, a number of the internationals who were sidelined in the autumn, including Logovi’i Mulipola, have been back in action and getting up to speed for the requirements of the Aviva Premiership.   During the Six Nations period, Tigers face Gloucester and Sale Sharks at Welford Road, plus London Irish and Newcastle Falcons away. They will all be fiercely-contested, the opposition will all scent blood if Tigers are anywhere away from top form or anywhere near under-strength.   This is a time that has perennially tested the Tigers, yet in the last decade we have seen the squad rally and come through it, even when they’ve had ground to make up – think back to 2008 or 2011.   Now it is down to the current squad to match that and get Tigers into those coveted positions in Champions Cup qualification, a Premiership semi-final alongside a run in the Cup.