Kiss X Sis Ova 1

If you want to watch chronologically then:
EP 1-3 of OVA > EP 1-9 of TV > EP 4 of OVA >EP 10-12 of TV > EP 5-12 of OVA.
It's also the same order it araied.

Thank you, I'm confused as well

Thanks!

I read the manga and watched both TV series and OVAs.
I tried to best match the chronological order of the manga with the anime (tv series + OVAs) based on some circumstances, like: the seasons of the year, Keita studying, Keita school uniform, some exclusive events, some events like the christmas (OVA 02) and etc.. trying at maximum to fit the exclusive events and changes that happens in the anime (tv series + OVAs) with the chronological order (manga <---> anime) without seem (too) awkward:
Ova 00 -> Ova 01 -> Ep. 01 -> Ep. 02 -> Ep. 03 -> Ep. 04 -> Ep. 05 -> Ep. 06 -> Ep. 08 -> Ep. 07 -> Ova 02 -> Ova 03 -> Ep. 09 -> Ep. 10 -> Ep. 11 -> Ep. 12 -> Ova 04 -> Ova 05 untill Ova 11.
PS.: OVA 00 can be also called OVA 01;
OVA 01 can be also called OVA 02;
OVA 02 can be also called .... and so on
and finnaly OVA 11 can be also called OVA 12.
It's just a question of numeration, in the end, we have a total of 12 OVA episodes regardless the numeration. But originally (and I dont know why) they are numbered 00, 01, 02 and so on, instead of start with 01, then 02 and and so on.
PS1.: Of course, the order does no match 100%, and is impossivel due to some exclusive things that happen only in the anime. But I think this is the best order if you want to watch in the chronological order based on the manga without seem awkward, as I already said aboce.
PS2.: If you'll follow this order, ignore the preview of the next episode at the end of each episode.
PS3.: Ye, I purposely switched Ep. 08 with Ep. 09. Why? Because of what I said in the beginning.
PS4.: You'll see Keita freguently alternating a black school uniform with a white school uniform. Both are from the same school and same grade, an so it does not mean that he changed of school or passed of grade. This constant alternation of school uniform (black <--> white) also happens in the manga. This keep like this untill certain point that
PS5.: Episode 01 (and if I'm not mistaken, also the episode 08 - ep 01 is certainty) is an 'anime only' episode, in other words, the events that happen on it does not exist in the manga.