There were many things that reminded him of Asuma. Smoking, of course, was the first. The second was whenever he looked at Kurenai or his team members. But that was alright; it filled him with good memories.
Another was laying back and watching the village. He was constantly reminded of and inspired by the memory of Asuma's lesson on the will of fire.
The one that got Shikamaru the most, however, was standing in the rain.
Rain made him think of that day.
He remembered standing and crying as he smelled the last of Asuma's smoke. As he said goodbye to his sensei.
The rain smells different to everyone. Some may say it smelled of humidity or a wet sidewalk. Some may even say it smelled as sweet as their best childhood memories.
But to Shikamaru the rain smelled of one thing and one thing only. To him it smelled like smoke.
And as Shikamaru stood outside of the academy, where they all first became a team, it rained. He inhaled deeply, enjoying the scent. Enjoying the way it triggered his best Team 10 memories. It brought forth memories of shogi game after shogi game and how Asuma always lost.
For that, Shikamaru loved the rain.
He looked up to the heavens and smiled, knowing that Asuma was smiling back.