@shakyric_lawson: Yoshi has demonstrated casting a kekkai inside the body of an ayakashi on the manga.
Second, Sonic is safe as long as he is outside it.. but he gets closed... well he is screwed... also inside Shinkai Yoshi is a high class reality bender since he can do what ever he so wishes inside it.
also end of series, Yoshi can control the Sinkai how ever he wants it thanks to his mosou technique... and if you add Karasumori.. it gets scarier.
But I agree Sonic could blitz Yoshi before he uses Shinkai... that is what Yoshi lacks.
He has shown to use Shinkai as a battle move...
also sorry if I brought up the Kekkaishi arguent.. :D I just didn't like what that dude said.. Sonic chars rule over fiction...
also I take it you haven't read Kekkaishi manga ja? Yoshi's manga counter part is super hax.