Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Perfect stem | Future stem | Imperfect stem | Short stem | Meaning |
| --- | --- | --- | --- | --- |
| hartu | hartuko | hartzen | har | 'take' |
| garbitu | garbituko | garbitzen | garbi | 'clean' |
| kendu | kenduko | kentzen | ken | 'take away, remove' |
| poztu | poztuko | pozten | poz | 'be/become happy' |
| ibili | ibiliko | ibiltzen | ibil | 'go about' |
| ikusi | ikusiko | ikusten | ikus | 'see' |
| iritsi | iritsiko | iristen | irits | 'arrive' |
| ireki | irekiko | irekitzen | ireki | 'open' |
| bete | beteko | betetzen | bete | 'fill' |
| jo | joko | jotzen | jo | 'strike' |
| hil | hilko | hiltzen | hil | 'die, kill' |
| egin | egingo | egiten | egin | 'make, do' |
| eman | emango | ematen | eman | 'give' |
| esan | esango | esaten | esan | 'say' |
Question:
What is the imperfect stem for the word that has a future stem of ikusiko?
Answer:
ikusten