Musoyama and makushita record

[Shoujirou Mizutori <MIZUTORI@shogun.matfys.lth.se>]

In the message on 
Date: Thu, 06 Oct 1994 18:19:21 -0700 (PDT)
From: abe@kaleida.com (Masumi Abe),

Abe-san introduced about Musoyama [sorry, deleted], and mentioned 
>
>He was ranked at the bottom of Makushita for Kyushu-basho in the same year,
>and won Makushita Yosho with 7-0 record in his very first basho as a
>professional sumo rikishi.
>
>-Masumi
>

I have some questions on his record in Makushita and
the speed promotion record from Makushita.

If I remember correctly, Oso (later Musoyama) spent only two basho
in Makushita. In both basho, he won 7-0. Is it correct?
And did he also won Yusho in the second basho? 
(7-0 in Makushita does not necessarily mean Yusho.)

Of course, to spend only two basho in Makushita is a record, but
he is not the first one. Actually I think quite a few Rikishi has
this record. I'm sure Wajima is one of them. (maybe first?)
I seems to remember Nagaoka(later Asashio) is also one.
How about Daishoyama? Kushimaumi? Other former Gakusei Yokozunas?

I think all of them are former Gakusei and/or Amature Yokozuna.
Usually, Rikishi has to climb up from to Jonokuchi, Jonidan, Sandamme,
then Makushita. However strong he become later, any Rikishi usually 
appear Makushita when he is just slightly better in Sandanme, but
not as strong to dominate in Makushita. (Everybody must have such stage.)
For them, it is hard to mark this record. Even those who has/used to have
speed promotion record from Jonokuchi to Juryo/Makuuchi don't have this 
record, if I know correctly. 
But those, who spend as an amature for a while and had good
record so as to be admitted his debut as Makushita, have fully matured
and could have already surpassed Makushita level.

Anyway, I want to ask
1) Correct record of Oso (Musoyama)?
2) How many persons have the record of "only two basho in Makushita"?
3) Who are they?
4) Is it really correct none of them start from Jonokuchi but all of them
start from Makushita?

Shoujirou Mizutori