Page 568 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

(It sounds great when I say that I am a graduate of the University of
Tokyo, but I was (in fact) a poor student who didn't study at all.)
+il I%k3
i
(el &'~EQ&&~z k ~ k%%$blbl/v~~s, j~llib~.%llib~%+@ ~*bk~t~
LTTdr,
(It sounds good when he says that he quit his company, but the truth of
the matter is that he was fired (lit. was made to quit).)

1. To iu to is used when something mentioned evokes some memory, as in
KS(A), Exs.(a) and (b), or when the speaker / writer wants to make a
remark which is different from what is expected, as in KS(B) and
Exs.(c) - (e). In both cases, the clause which follows X to iu to is a
response (an involuntary action or a state of mind) caused by X.
2. To iu to is also used to question the meaning of a word or phrase men-
tioned by the interlocutor, as in (1).

37mi&3T-m?
(Do you like karaoke?)
?I?$+-L: {E3 /EL\%-$] L:?
(What do you mean by karaoke? (lit. When you mention
karaoke, (what do you mean by that?))

[Related Expression]
To ieba is similar to to iu to. However, to iu to is used in the situations men-
tioned in Note 1, whereas to ieba is used when the speaker wants to present
what has just been mentioned as a new topic. Compare [I] and [Z].

[2] A: $, +~'J~~'J>X=I$>L;~%$&T~~&/~TT~
(I have a friend from San Francisco visiting me now.)