Page 605 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

(I finally found a book I had been looking for at a second-
hand bookstore in Kanda.)

As explained in Note 1 above, Wt6 tends to occur with a negative state-
ment, so for example in [3a] the choice of t6to indicates the speaker /
writer's dislike of the winter, whereas, the choice of yatto indicates his
liking of the winter. In [3b] the choice of tot6 indicates the speaker 1
writer's unhappiness about the man's quitting the job, whereas the
choice of yaffo indicates his happiness about the guy's quitting the job.

[31 a. FS {titi /~=t) .e9rw:,
(The winter finally came.)
b. ?a)%'iiWk~ It3ti/T?t) &&7':,
(The man quit the company in the end.)
Note also that yaffo cannot be used with a negative predicate, at'fol-,
lows.
[4] a. 2:XStvdi It323 /*T~t:l 1f-74-b:%3-&tv
T LJ:,
(Smith didn't show up at the party after all.)
b. ;rs < ~f:&%di {ti ti/*T7tl R9j5'?J 3@tvTLI:,
(The purse I lost was not found after all.)
11. Another similar adverb tsui ni can replace tot6 and yaffo, when the main
verb is affirmative, but when it is negative, it can replace only t6t6.

h56
[6] a. 3-r'J-di (7L\tZ/titi/*T7t1 1f--7i--K%
tx;rsj5x97L
(Cathy didn't show up at the party after all.)