A) League of Legends started in Season 1, i don't know much about it but FNaticRC was the dominating team at this time.
Season 2 was the days of Moscow 5 (gambit gaming) who dominated all of NA, China and even South Korea. This time was too the time of Azubu Frost & Blaze and Najin Sword. TSM was the big one in NA too.
As the EU & NA tournaments was going on it was always CLG EU (now split into Alliance and EG) vs Moscow 5, this time it was IEM, dreamhack etc that was the online tournaments you could watch since LCS didnt come.
At world a surprise team in Taipei Assasins (TPA) came, they had been winning tournaments before but wasn't doing great before worlds, but they ended up in the semis after beating Najin Sword (2-0) vs Moscow 5 (they beat IG 2-0), this match was a 2-1 in favour of TPA, m5 dominated the first match and the second match they self saidn they made too many mistakes to learn from the Secret Nidalee comp of TPA, and the Third match was the special team comp TPA ran crushing M5's playstyle.
CLG.EU had some of the longest series against Team WE in quarter, getting ddosed and having 40-50min games in all 3 games, ending they won 2-1 in a nailbiter of a set. But they lost quite badly vs Azubu Frost (2-1) in semis.
TPA won Season 2 world championship 3-1 over Azubu Frost and here ended the season.
Now season 3 started, and LCS came. Fnatic won the League 1 game over Gambit, and 3-2 in playoffs meanwhile TSM won 3-2 over Good Gaming University (coast)
The NeXT LCs split was one of the tightest one ever, With a four way tie for 2nd Place and Lemondogs at the top. NA had entered the c9 era where they dominated everything With Vulcan on a second. in Playoffs TSM beat Vulcan for a second Place, and Fnatic won 3-1 over lemondogs and Gambit barely won 2-1 over EG.
SKT T1 (k) won the world championship and walked into going undefeated thru hole OGN Winter and big parts of Masters.
Season 4 is so recent u easily find it )
B)
www.leaguepedia.com
I dont think japan has a own server, and i haven't seen Japanese pro's.