I understand that this discussion is old, but I'm going to liven things up with what I have noticed.
1. The obvious: Shinichi and Kaito look alike, as well as their fathers.
2. There is no way that Shinichi and Kaito have the same mother, since Kaito's mother is
and Shinichi's mother should have still been an actress at the same time, which would have kept her busy.
Now for some speculations:
1. Names can be changed, even last names. So the difference in names doesn't count for much.
2. If either Yuusaku or Touichi changed their names, would they still refer to each other as brothers if that was their relationship? This is an especially good point to look at seeing as Yuusaku became a mystery author who assisted the police and Kouichi became the phantom thief. Not letting others know they were brothers would allow them to continue life normally without being in each others way, especially if Touichi were found out. If that happened and they were known brothers, Yuusaku would have lost a great deal of credibility as a detective.
3. It is possible that Yuukiko only got lessons from Touichi because Yuusaku asked.
So, I do not believe Shinichi and Kaito are long lost brothers. Although the idea is marvelous, it is completely illogical. I personally believe Shinichi and Kaito are cousins whose fathers, who were brothers, changed their last names to protect each other and wound up in a friendly rivalry.
Also, I'm wondering if Shinichi and Kaito are actually fighting different branches of the same organizations since both of their targets have to do with
Hope this starts a nice, lively discussion
Oh, and I believe Shinichi and Kaito are tied. Shinichi is a detective, his job is not to capture but to comprehend, and I'd say he figured out all the tricks. And Kaito always got away. So even.
"Courage is a word that gives you the strength to do what's right, you should not use it as an excuse to murder someone." -Mouri Ran
"Fear of death is worse than death itself." - Akai Shuuichi
"A thief is a creative artist who takes his prey in style... But a detective is nothing more than a critic, who follows our footsteps..." - Kaito Kid 1412
"A trick is nothing but a puzzle mankind came up with. If you use your head, you can uncover the logical answer." "I don't know why you would kill someone but as for saving someone... a logical mind isn't needed, right?" - Kudou Shinichi