At the end of episode 220 of Detective Conan, "The Client Full of Lies", Heiji appears and explains the reason behind the fake name "Reiko" to Conan that it was to conceal the fact that his mom is from Osaka.

But that doesn't explain why she has to lie about her being good at cooking and her allergy to dust. If she were to hide her identity, she need not lie about the cooking and the allergies. Conan wouldn't be able to find out even if he knew that she was from Osaka since it was his first time meeting Heiji's mother.

Why did she have to go that far? Or was it part of her test for Mouri to figure out her real identity?

Even if it's the case, I bet no one's going to be able to deduce that she is Heiji's mother because first, it's impossible to even know the true identity of a person just by knowing her hobbies or skills. Unless she has a distinctive quality in which the Hattori's are famous for.

Second, Conan did not even know a thing about Heiji's mom. The test was actually for Shinichi but since he wasn't there, she tried Mouri instead. No matter how good Conan's deductions were, it was impossible for him to expose her real identity as Heiji's mom and her real intentions. They were even surprised when she revealed her true identity as Heiji's mom since Heiji didn't even look like her.

So, why did she have to lie about all the stuff?

  • she didn't test Mouri to figure out her real identity, but only to figure out that she was lying.
    – Darjeeling
    Nov 16, 2014 at 4:57
  • But she didn't explain why she lied about she came from Osaka, I guess maybe she thought that somehow Mouri will realize her relation with Heiji (which is quite impossible as you said)
    – Darjeeling
    Nov 16, 2014 at 5:05
  • yeah i don't think Mouri really knows her as Heiji's mom.. Heiji's mom knows about Mouri as shown in the scene where Mouri was in the hospital, visiting Heiji
    – user8802
    Nov 16, 2014 at 5:30

1 Answer 1


Her first three lie about her cooking skill, allergies, and the fact that she is married was intended from her to test Mouri whether he noticed it or not, not to hide her real identity as Heiji's mother. But her third lie came unintentionally from her when she was about to say cold coffee. Maybe she did it accidentally and has to cover it with saying "Reiko".

So she lied to test Mouri, not to hide her real identity.

Another possibility is maybe she didn't know whether Heiji told his friend about her hobby and others or not, and she did that because she didn't want to know that she is Heiji's mother and make all her lies vain.

  • oh yeah you're right. the lie was to test whether Mouri would be able to figure out that she lied or not. but i don't think she intended to lie about her hobbies to conceal hear identity. i mean even if they knew that she has those hobbies and she is from Osaka, there a lots of women around her age from Osaka who have the same hobbies as her. it's possible to deduce that she's from this place who works with this occupation and likes this and that BUT it's really impossible to deduce correctly that she is Hattori's mother, considering that Heiji looked very far like his mom.
    – user8802
    Nov 16, 2014 at 9:01

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